Benzo[4,5]thieno[2,3-c]pyridine and Benzo[4,5]furo[2,3-c]pyridine Derivatives Useful as Inhibitors of Phosphodiesterase

ABSTRACT

The present invention relates to novel β-carboline derivatives of the general formula 
                 
         wherein all the variables are as described within the specification, useful as phosphodiesterase inhibitors. The present invention further relates to use of the described derivatives for the treatment of diseases and conditions related to PDE, for example male erectile dysfunction.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of prior application U.S. Ser. No.09/847,767, filed May 2, 2001, now issued as U.S. Pat. No. 6,492,358 onDec. 10, 2002, which claims priority from U.S. provisional applicationSer. No. 60/204,667, filed May 17, 2000, the contents of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to novel β-carboline derivatives, usefulas phosphodiesterase inhibitors. The invention further relates tosynthesis of the β-carboline derivatives and intermediates used in theirpreparation. The present invention additionally relates to use of thedescribed derivatives for the treatment of diseases and conditionsrelated to PDE, for example male erectile dysfunction.

BACKGROUND OF THE INVENTION

Erectile dysfunction (ED) is defined as the inability to achieve ormaintain an erection sufficiently rigid for satisfactory sexualintercourse. Currently it is estimated that approximately 7-8% of themale population suffers from some degree of ED, the equivalent of atleast 20 million men in the United States alone. Since the likelihood ofED increases with age, it is projected that the incidence of thiscondition will rise in the future as the average age of the populationincreases.

Male erectile dysfunction may be the consequence of psychogenic and/ororganic factors. Although ED is multi-factorial, certain sub-groupswithin the male population are more likely to present with the symptomsof the disorder. In particular, patients with diabetes, hypertension,heart disease, and multiple sclerosis have a particularly highprevalence of ED. In addition, patients who take certain classes ofdrugs such as antihypertensives, antidepressants, sedatives, andanxiolytics are more prone to suffer from ED.

Treatments for ED include a variety of pharmacologic agents, vacuumdevices, and penile prostheses. Among the pharmacologic agents,papaverine, phentolamine, and alprostadil are currently used inpractice. These agents are only effective after direct intracavernosalor intraurethral injection, and are associated with side effects such aspriapism, fibrosis, penile pain and hematoma at the injection site.Vacuum devices are a noninasive alternative treatment for ED. Thesedevices produce an erection by creating a negative pressure around theshaft of the penis resulting in an increased blood flow into the corpuscavernosum via passive arterial dilation. Although this form of therapyis frequently successful in ED of organic origin, complaints include thelack of spontaneity and the time involved in using a mechanical device,and difficulty and discomfort with ejaculation. A variety of semi-rigidor inflatable penile prostheses have been used with some success,particularly in diabetic men. These devices are generally consideredwhen other treatment options have failed, and are associated with anincreased risk of infection and ischemia.

Recently, the phosphodiesterase V (PDEV) inhibitor, sildenafil (Viagra®)was approved by the FDA as an orally effective medication for thetreatment of ED. Sildenafil,5-[2-ethoxy-5-(4-methylpiperazin-1-ylsulphonyl)phenyl]-1-methyl-3-n-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7-oneand a number of related analogs and their use as antianginal agents aredescribed in U.S. Pat. Nos. 5,250,534 and 5,346,901. The use ofsildenafil and related analogs for treating male erectile dysfunction isdescribed in PCT International Application Publication No. WO 94/28902,published Dec. 22, 1994. In clinical studies, the drug improved sexualfunction in about 70% of the men who suffer from ED of psychogenic ororganic etiology. However, the drug showed less dramatic efficacy inpatients who had undergone a radical prostatectomy, with improvederections in 43% of patients who took sildenafil versus 15% on placebo.In addition, the use of sildenafil is associated with severalundesirable side effects including headache, flushing and disruptedcolor vision which result from non-selective effects on a variety oftissues. In spite of these shortcomings, the drug is viewed by patientsas preferable to other treatments which involve the introduction ofmedication directly into the penis via injection, the use of an externaldevice or a surgical procedure.

Daugan et. al, in U.S. Pat. No. 5,859,009 (EP 0740668 B1 and WO9519978)describe the synthesis of tetracyclic derivatives as inhibitors ofcyclic guanosine 3′,5′-monophosphate specifically phosphodiesterase, andtheir use in treating cardiovascular disorders. Daugan et. al., inWO97/03675 teach the use of tetracyclic derivatives for the treatment ofimpotence.

Bombrun et al., in WO 97/43287 describe a series of carbolinederivatives, more specifically 2-(substituted alkyl carbonyl)substituted carboline derivatives and their use in treatingcardiovascular disorders as inhibitors of cyclic guanosine3,5-monophosphate, specifically phosphodiesterase.

Ellis et. al., in WO 94/28902 and EP0702555 B1 describes a series ofpyrazolpyrimidinone derivatives and their use in treating erectiledysfunction. Campbell, S. F. in WO96/16657 teaches the use of bicyclicheterocyclic compounds for the treatment of impotence(pyrazolopyrimidones); while Campbell et al, in WO,96/16644 teach theuse of selective cGMP PDE inhibitors for the treatment of erectiledysfunction.

Ohashi et al., in WO9745427 disclose tetracyclic pyridocarbazolederivatives having cGMP PDE inhibitory effects.

Fourtillan et. al., in WO 96/08490 A1 describe a series of carbolinederivatives and their use in the treatment of diseases associated withmelatonin activity disorders. Ueki et. al., in U.S. Pat. No. 5,126,448describe pyridine and 1,2,3,4-tetrahydropyridine derivatives useful aspsychotropic drugs having antianxiety effects. Atkinson et. al., in U.S.Pat. No. 3,328,412 describe 1-aryl- and1-heteroaryl-2-acly-1,2,3,4-tetrahydro-β-carboline derivatives havinglong lasting analgesic properties.

Sexually stimulated penile erection results from a complex interplay ofphysiological processes involving the central nervous system, theperipheral nervous system, and the smooth muscle. Specifically, releaseof nitric oxide from the non-adrenergic, non-cholinergic nerves andendothelium activates guanylyl cyclase and increases intracellular cGMPlevels within the corpus cavernosum. The increase in intracellular cGMPreduces intracellular calcium levels, resulting in trabecular smoothmuscle relaxation, which, in turn, results in corporal volume expansionand compression of the sub-tunical venules leading to penile erection.

PDEV has been found in human platelets and vascular smooth muscle,suggesting a role for this enzyme in the regulation of intracellularconcentrations of cGMP in cardiovascular tissue. In fact, inhibitors ofPDEV have been shown to produce endothelial-dependent vasorelaxation bypotentiating the increases in intracellular cGMP induced by nitricoxide. Moreover, PDEV inhibitors selectively lower the pulmonaryarterial pressure in animal models of congestive heart failure andpulmonary hypertension. Hence in addition to their utility in ED, PDEVinhibitors would likely be of therapeutic benefit in conditions likeheart failure, pulmonary hypertension, and angina.

Agents that increase the concentration of cGMP in penile tissue, eitherthrough enhanced release or reduced breakdown of cGMP, are expected tobe effective treatments for ED. The intracellular levels of cGMP areregulated by the enzymes involved in its formation and degradation,namely the guanylate cyclases and the cyclic nucleotidephosphodiesterases (PDEs). To date, at least nine families of mammalianPDEs have been described, five of which are capable of hydrolyzing theactive, cGMP, to the inactive, GMP, under physiological conditions (PDEsI, II, V, VI, and IX). PDE V is the predominant isoform in human corpuscavernosum. Inhibitors of PDEV, therefore, would be expected to increasethe concentration of cGMP in the corpus cavernosum and enhance theduration and frequency of penile erection.

Additionally, selective PDE inhibitors are known to be useful in thetreatment of various disorders and conditions including male erectiledysfunction (ED), female sexual arousal dysfunction, female sexualdysfunction related to blood flow and nitric oxide production in thetissues of the vagina and clitoris, premature labor, dysmenorrhea,cardiovascular disorders, atherosclerosis, arterial occlusive disorders,thrombosis, coronary rest stenosis, angina pectoris, myocardialinfarction, heart failure, ischemic heart disorders, hypertension,pulmonary hypertension, asthma, intermittent claudication and diabeticcomplications.

Accordingly, it is an object of the invention to identify compoundswhich increase the concentration of cGMP in penile tissue through theinhibition of phosphodiesterases, specifically PDEV. It is anotherobject of the invention to identify compounds which are useful for thetreatment of sexual dysfunction, particularly erectile dysfunctionand/or impotence in male animals and sexual dysfunction in femaleanimals. Still another object of the invention is to identify methodsfor treating sexual dysfunction, especially erectile dysfunction, usingthe compounds of the present invention.

It is another object of the invention to identify compounds which areuseful for the treatment of conditions of disorders mediated by PDEV,such as male erectile dysfunction, female sexual dysfunction,cardiovascular disorders, atherosclerosis, arterial occlusive disorders,thrombosis, coronary rest stenosis, angina pectoris, myocardialinfarction, heart failure, ischemic heart disorders, hypertension,pulmonary hypertension, asthma, intermittent claudication or diabeticcomplications.

We now describe a series of β-carboline derivatives with the ability toinhibit phosphodiesterase type V in enzyme assays and increase theconcentration of cGMP in cavernosal tissue in vitro.

SUMMARY OF THE INVENTION

The present invention provides novel β-carboline derivative compoundsuseful as phosphodiesterase inhibitors. More particularly, the presentinvention is directed to compounds of the general formula (I):

wherein

-   -   R¹ is independently selected from the group consisting of        halogen, nitro, hydroxy, C₁C₈alkyl, C₁-C₈alkoxy, —NH₂, —NHR^(A),        —N(R^(A))₂, —O—R^(A), —C(O)NH₂, —C(O)NHR^(A), —C(O)N(R^(A))₂,        —NC(O)—R^(A), —SO₂NHR^(A), —SO₂N(R^(A))₂, phenyl (optionally        substituted with 1 to 3 R^(B)) and heteroaryl (optionally        substituted with 1 to 3 R^(B));    -   where each R^(A) is independently is independently selected from        the group consisting of C₁-C₈alkyl, aryl (optionally substituted        with 1 to 3 R⁸), C₁-C₈aralkyl (optionally substituted with 1 to        3 R^(B)) and heteroaryl (optionally substituted with 1 to 3        R^(B));    -   where each R^(B) is independently selected from the group        consisting of halogen, hydroxy, nitro, cyano, C₁-C₈alkyl,        C₁-C₈alkoxy, C₁-C₈alkoxycarbonyl, carboxyC₁-C₈alkyl,        C₁-C₈alkylsulfonyl, trifluoromethyl, trifluoromethoxy, amino,        acetylamino, di(C₁-C₈alkyl)amino,        di(C₁-C₈alkyl)aminoC₁-C₈alkoxy,        di(C₁-C₈alkyl)aminoacetylC₁-C₈alkyl,        di(C₁-C₈alkyl)aminoacetylamino, carboxyC₁-C₈alkylcarbonylamino,        hydroxyC₁-C₈alkylamino, NHR^(A), N(R^(A))₂ and        heterocycloalkylC₁-C₈alkoxy;    -   n is an integer from 0 to 4;    -   X is selected from the group consisting of O, S and NR^(D);    -   where R^(D) is selected from the group consisting of hydrogen,        hydroxy, —OR^(A), C₁-C₈alkyl (wherein the alkyl is optionally        substituted with one to three substituent independently selected        from halogen, carboxy, amino, C₁-C₈alkylamino,        di(C₁-C₈alkyl)amino, C₁-C₈alkoxycarbonyl, heteroaryl or        heterocycloalkyl), heteroaryl and heteroarylcarbonyl (wherein        the heteroaryl may be optionally substituted with phenyl or        substituted phenyl, where the phenyl substituents are one to        three R^(B));    -   R² is selected from the group consisting of C₅-C₁₀alkyl        (optionally substituted with 1 to 3 R^(C)), aryl (optionally        substituted with 1 to 3 R^(B)), heteroaryl (optionally        substituted with 1 to 3 R^(B)) and heterocycloalkyl (optionally        substituted with 1 to 3 R^(B));    -   where each R^(C) is independently selected from the group        consisting of halogen, hydroxy, nitro, NH₂, NHR^(A) and        N(R^(A))₂;    -   Z is selected from the group consisting of CH₂, CHOH and C(O);        provided that when Z is CHOH or C(O), then X is NH;    -   R⁴ is selected from the group consisting of hydrogen, hydroxy,        carboxy, C₁-C₆alkylcarbonyl, C₁-C₆alkoxylcarbonyl,        di(C₁-C₈alkyl)aminoalkoxycarbonyl,        di(C₁-C₈alkyl)aminoC₁-C₈alkylaminocarbonyl, and —COR^(F);    -   where R^(F) is selected from the group consisting of C₁-C₈alkyl,        NH₂, NHR^(A), NR^(A) ₂, —C₁-C₈alkyl-NH₂, —C₁-C₈alkyl-NHR^(A),        —C₁-C₈alkyl-NR^(A) ₂ and —NH—C₁-C₈alkyl-NR^(A) ₂;    -   a is an integer from 0 to 1;    -   Y is selected from the group consisting of CH₂, C(O), C(O)O,        C(O)—NH and SO₂;    -    is selected from the group consisting of naphthyl, heteroaryl        and heterocycloalkyl;    -   m is an integer from 0 to 2;    -   R³ is independently selected from the group consisting of        halogen, nitro, C₁-C₈alkyl, C₁-C₈alkoxy, trifluoromethyl,        trifluoromethoxy, phenyl (optionally substituted with 1 to 3        R^(B)), phenylsulfonyl, naphthyl, C₁-C₈aralkyl, heteroaryl        (optionally substituted with 1 to 3 R^(B)), NH₂, NHR^(A) and        N(R^(A))₂;    -   provided that when    -    is 2-furyl or 2-thienyl, then m is an integer from 1 to 2;    -   and pharmaceutically acceptable salts thereof.

Illustrative of the invention is a pharmaceutical composition comprisinga pharmaceutically acceptable carrier and any of the compounds describedabove. An illustration of the invention is a pharmaceutical compositionmade by mixing any of the compounds described above and apharmaceutically acceptable carrier. Illustrating the invention is aprocess for making a pharmaceutical composition comprising mixing any ofthe compounds described above and a pharmaceutically acceptable carrier.

Exemplifying the invention are methods of treating sexual dysfunction,for example, male erectile dysfunction, impotence, female sexualdysfunction, for example female sexual arousal dysfunction, femalesexual dysfunction related to blood flow and nitric oxide production inthe tissues of the vagina and clitoris, premature labor and/ordysmenorrhea in a subject in need thereof comprising administering tothe subject a therapeutically effective amount of any of the compoundsor pharmaceutical compositions described above.

An example of the invention is a method for increasing the concentrationof cGMP in penile tissue through the inhibition of phosphodiesterases,specifically PDEV, in a male subject in need thereof comprisingadministering to the subject an effective amount of any of the compoundsor pharmaceutical compositions described above.

Further exemplifying the invention is a method of producingendothelial-dependent vasorelaxation by potentiating the increases inintracellular cGMP induced by nitric oxide in a subject in need thereofcomprising administering to the subject an effective amount of any ofthe compounds or pharmaceutical compositions described above.

Further illustrating the invention is a method of treating a conditionselected from the group consisting of male erectile dysfunction (ED),impotence, female sexual dysfunction, female sexual arousal dysfunction,female sexual dysfunction related to blood flow and nitric oxideproduction in the tissues of the vagina and clitoris, premature labor,dysmenorrhea, cardiovascular disorders, atherosclerosis, arterialocclusive disorders, thrombosis, coronary rest stenosis, anginapectoris, myocardial infarction, heart failure, ischemic heartdisorders, hypertension, pulmonary hypertension, asthma, intermittentclaudication and diabetic complications in a subject in need thereofcomprising administering to the subject a therapeutically effectiveamount of any of the compounds or pharmaceutical compositions describedabove.

An example of the invention is the use of any of the compounds describedabove in the preparation of a medicament for: (a) treating sexualdysfunction, especially male erectile dysfunction, (b) treatingimpotence, (c) increasing the concentration of cGMP in penile tissuethrough inhibition of phosphodiesterase, especially PDEV and/or (d)treating a condition selected from the group consisting of prematurelabor, dysmenorrhea, cardiovascular disorders, atherosclerosis, arterialocclusive disorders, thrombosis, coronary rest stenosis, anginapectoris, myocardial infarction, heart failure, ischemic heartdisorders, hypertension, pulmonary hypertension, asthma, intermittentclaudication and diabetic complications in a subject in need thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides novel β-carboline derivatives useful forthe treatment of sexual dysfunction, particularly male erectiledysfunction (ED). Although the compounds of the present invention areuseful primarily for the treatment of male sexual dysfunction orerectile dysfunction, they may also be useful for the treatment offemale sexual dysfunction, for example female sexual arousaldysfunction, female sexual dysfunction related to blood flow and nitricoxide production in the tissue of the vagina and clitoris, and ofpremature labor and dysmenorrhea.

More particularly, the compounds of the present invention are of theformula (I):

wherein all variables are as defined above.

Preferably, n is 0. Preferably, m is an integer from 0 to 1.

In an embodiment of the present invention X is selected from S orNR^(D), wherein R^(D) is selected from the group consisting of hydrogen,haloC₁-C₆alkyl, di(C₁-C₄alkyl)aminoC₁-C₆alkyl, heteroaryl,heteroarylC₁-C₄alkyl, heterocycloalkyC₁-C₄alkyl, carboxyC₁-C₄alkyl,C₁-C₄alkoxycarbonylC₁-C₄alkyl and heteroarylcarbonyl; wherein theheteroaryl is further optionally substituted with phenyl or substitutedphenyl, wherein the substituents on the phenyl are one to twoindependently selected from R^(B); and wherein each R^(B) isindependently selected from the group consisting of halogen, nitro,C₁-C₄alkyl, C₁-C₄alkoxy, trifluoromethyl, trifluoromethoxy, amino anddi(C₁-C₄alkyl)amino. Preferably, X is selected from S or NR^(D), whereR^(D) is selected from the group consisting of hydrogen,di(methyl)aminoethyl, di(methyl)amino-n-propyl, di(ethyl)aminoethyl,di(ethyl)amino-n-butyl, N-pyrrolidinylethyl, N-morpholinylethyl,2-pyridylmethyl, 4-pyridylmethyl, 5-(4-methylphenyl)-2-pyrimidinyl,carboxymethyl, carboxyethyl, 4-chloro-n-butyl,2-(5-(3-trifluoromethylphenyl)furyl)carbonyl,2-(5-(3-nitrophenyl)furyl)carbonyl, methoxycarbonylmethyl,methoxycarbonylethyl and 2-benzoxazolyl. More preferably, X is NR^(D),where R^(D) is selected from the group consisting of hydrogen,di(methyl)aminoethyl, 4-pyridylmethyl, 2-pyridylmethyl,N-morpholinylethyl, carboxyethyl, carboxymethyl, di(ethyl)aminoethyl,N-pyrrolidinylethyl and 5-(4-methylphenyl)-2-pyrimidinyl. Mostpreferably, X is NR^(D), where R^(D) is selected from the groupconsisting of hydrogen, di(methyl)aminoethyl, N-morpholinylethyl,carboxymethyl and N-pyrrolidinylethyl;

Preferably, Z is selected from the group consisting of CH₂ and C(O);provided that when Z is C(O), then X is NH.

Preferably, Y is selected from the group consisting of C(O), SO₂ andCH₂. More preferably, Y is selected from the group consisting of C(O)and CH₂. Most preferably, Y is C(O).

In an embodiment of the present invention

is selected from the group consisting of naphthyl and heteroaryl.Preferably,

is selected from the group consisting of naphthyl, 2-pyrimidinyl,2-furyl, 3-furyl, 2-benzofuryl, 2-theinyl, 2-benzothienyl,2-benzothiazolyl, 2-benzoxazolyl, 2-benzimidazolyl, 4-thiazolyl,2-thiazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 3-(1,2,5-triazolyl),4-isoxazolyl, 2-pyridyl and 3-pyridyl. More preferably,

is selected from the group consisting of naphthyl, 2-pyrimidinyl,2-furyl, 2-benzofuryl, 2-thienyl, 2-benzothienyl, 2-benzothiazolyl,2-benzoxazolyl, 2-thiazolyl, 4-thiazolyl and 2-pyridyl.Most preferably,

is selected from the group consisting of 2-pyrimidinyl, 2-furyl,2-benzofuryl, 2-benzoxazolyl, 2-thiazolyl and 2-pyridyl.

In an embodiment of the present invention, R² is selected from the groupconsisting of 3,4-methylenedioxyphenyl,3,4-(difluoro)methylenedioxyphenyl, 2,3-dihydrobenzofuryl,2,3-dihydrobenzo-[1,4]-dioxin-6-yl, pyridyl, phenyl and substitutedphenyl; wherein the phenyl substituents are one to two substituentsindependently selected from halogen, C₁-C₄alkyl, C₁-C₄alkoxy,trifluoromethyl, cyano, nitro, C₁-C₄alkoxycarbonyl, di(C₁-C₄alkyl)aminoor di(C₁-C₄alkyl)aminoC₁-C₄alkoxy. Preferably, R² is selected from thegroup consisting of phenyl, 3,4-methylenedioxyphenyl,3,4-(difluoro)methylenendioxyphenyl, 2,3-dihydrobenzofuryl,2,3-dihydrobenzo-[1,4]-dioxin-6-yl, 4-pyridyl, 3-pyridyl, 4-cyanophenyl,3-nitrophenyl, 4-nitrophenyl, 4-trifluoromethylphenyl, 4-methoxyphenyl,3,4-dimethylphenyl, 3,5-dimethylphenyl, 3,4-dimethoxyphenyl,3-trifluoromethyl-4-chlorophenyl, 3,4-dichlorophenyl, 4-chlorophenyl,4-methoxycarbonylphenyl, 3,4-dimethoxyphenyl, 4-(dimethylamino)phenyland 4-(N-(3-dimethylamino)-n-propoxy)phenyl. More preferably, R² isselected from the group consisting of 3,4-methylenedioxyphenyl,2,3-dihydrobenzofuryl and 2,3-dihydrobenzo-[1,4]-dioxin-6-yl. Mostpreferably, R² is selected from the group consisting of3,4-methylenedioxyphenyl and 2,3-dihydrobenzofuryl.

Preferably, R⁴ is selected from the group consisting of hydrogen,carboxy, C₁-C₄alkoxycarbonyl, di(C₁-C₄alkyl)aminoC₁-C₄alkoxycarbonyl anddi(C₁-C₄alkyl)aminoC₁-C₄alkylaminocarbonyl. More preferably, R⁴ isselected from the group consisting of hydrogen, carboxy,dimethylaminoethoxycarbonyl, dimethylaminoethylaminocarbonyl andmethoxycarbonyl. Most preferably, R⁴ is hydrogen.

In an embodiment of the present invention, R³ is independently selectedfrom the group consisting of halogen, nitro, C₁-C₄alkyl, C₁-C₄alkoxy,trifluoromethyl, C₁-C₄aralkyl, pyrazinyl, pyridyl, halogen substitutedpyridyl, dimethyl substituted imidazolyl, phenyl, phenylsulfonyl andsubstituted phenyl; wherein the substituents on the phenyl are one ormore substituents independently selected from halogen, hydroxy,C₁-C₄alkyl, C₁-C₄alkoxy, trifluoromethyl, trifluoromethoxy, nitro,amino, acetylamino, C₁-C₄alkylsulfonyl, carboxyC₁-C₄alkylcarbonylamino,hydroxyC₁-C₄alkylamino, di(C₁-C₄alkyl)aminoC₁-C₄alkoxy,di(C₁-C₄alkyl)aminoacetylamino or heterocycloalkylC₁-C₄alkoxy.Preferably, R³ is independently selected from the group consisting ofchloro, bromo, methyl, n-propyl, t-butyl, methoxy, trifluoromethyl,nitro, phenyl, benzyl, phenylsulfonyl, 4-hydroxyphenyl, 4-chlorophenyl,4-methylphenyl, 3,4-dimethoxyphenyl, 3-trifluoromethylphenyl,4-trifluoromethylphenyl, 5-trifluoromethylphenyl, 4-methoxyphenyl,2-nitrophenyl, 3-nitro-4-nitrophenyl, 3-aminophenyl, 4-aminophenyl,2-nitro-4-chlorophenyl, 2-nitro-4-methylphenyl,2-nitro-4-methylsulfonylphenyl, 3-acetylaminophenyl,4-acetylaminophenyl, 4-(3-carboxy-n-propyl)carbonylaminophenyl,2-chloro-5-trifluoromethylphenyl, 4-(4-hydroxy-n-butyl)aminophenyl,2-(dimethylamino)acetylaminophenyl, 4-[2-(N-pyrrolidinyl)ethoxy]phenyl,4-[2-(4-morpholinyl)ethoxy]phenyl, 4-(2-(dimethylamino)ethoxy)phenyl,4-pyrazinyl, 2,3-dimethyl-3H-imidazolyl, 2-pyridyl and 3-pyridyl. Morepreferably, R³ is selected from the group consisting of bromo, t-butyl,methoxy, trifluoromethyl, nitro, phenyl, 4-chlorophenyl,3,4-dimethoxyphenyl, 3-trifluoromethylphenyl, 4-methylphenyl,4-methoxyphenyl, 2-nitrophenyl, 3-nitrophenyl, 4-nitrophenyl,3-aminophenyl, 2-nitro-4-chlorophenyl, 2-nitro-4-methylphenyl,2-nitro-4-methylsulfonylphenyl,4-(3-carboxy-n-propyl)carbonylaminophenyl2-chloro-5-trifluoromethylphenyl, 4-(4-hydroxy-n-butyl)aminophenyl,2-2-(dimethylamino)acetylaminophenyl, 4-pyrazinyl 2-pyridyl and2,3-dimethyl-3H-imidazol-4-yl. Most preferably, R³ is selected from thegroup consisting of t-butyl, methoxy, nitro, phenyl, 4-chlorophenyl,4-methylphenyl, 4-methoxyphenyl, 3,4-dimethoxyphenyl,3-trifluoromethylphenyl, 2-nitrophenyl, 3-nitrophenyl, 4-nitrophenyl,3-aminophenyl, 2-nitro-4-methylsulfonylphenyl,2-(dimethylamino)acetylaminophenyl, 2-pyridyl and2,3-dimethyl-3H-imidazol-4-yl.

For use in medicine, the salts of the compounds of this invention referto non-toxic “pharmaceutically acceptable salts.” Other salts may,however, be useful in the preparation of compounds according to thisinvention or of their pharmaceutically acceptable salts. Suitablepharmaceutically acceptable salts of the compounds include acid additionsalts which may, for example, be formed by mixing a solution of thecompound with a solution of a pharmaceutically acceptable acid such ashydrochloric acid, sulfuric acid, fumaric acid, maleic acid, succinicacid, acetic acid, benzoic acid, citric acid, tartaric acid, carbonicacid or phosphoric acid. Furthermore, where the compounds of theinvention carry an acidic moiety, suitable pharmaceutically acceptablesalts thereof may include alkali metal salts, e.g., sodium or potassiumsalts; alkaline earth metal salts, e.g., calcium or magnesium salts; andsalts formed with suitable organic ligands, e.g., quaternary ammoniumsalts. Thus, representative pharmaceutically acceptable salts includethe following:

-   -   acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate,        bitartrate, borate, bromide, calcium edetate, camsylate,        carbonate, chloride, clavulanate, citrate, dihydrochloride,        edetate, edisylate, estolate, esylate, fumarate, gluceptate,        gluconate, glutamate, glycollylarsanilate, hexylresorcinate,        hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate,        iodide, isothionate, lactate, lactobionate, laurate, malate,        maleate, mandelate, mesylate, methylbromide, methylnitrate,        methylsulfate, mucate, napsylate, nitrate, N-methylglucamine        ammonium salt, oleate, pamoate (embonate), palmitate,        pantothenate, phosphate/diphosphate, polygalacturonate,        salicylate, stearate, sulfate, subacetate, succinate, tannate,        tartrate, teoclate, tosylate, triethiodide and valerate.

The present invention includes within its scope prodrugs of thecompounds of this invention. In general, such prodrugs will befunctional derivatives of the compounds which are readily convertible invivo into the required compound. Thus, in the methods of treatment ofthe present invention, the term “administering” shall encompass thetreatment of the various disorders described with the compoundspecifically disclosed or with a compound which may not be specificallydisclosed, but which converts to the specified compound in vivo afteradministration to the patient. Conventional procedures for the selectionand preparation of suitable prodrug derivatives are described, forexample, in “Design of Prodrugs”, ed. H. Bundgaard, Elsevier, 1985.

Where the compounds according to this invention have at least one chiralcenter, they may accordingly exist as enantiomers. Where the compoundspossess two or more chiral centers, they may additionally exist asdiastereomers. It is to be understood that all such isomers and mixturesthereof are encompassed within the scope of the present invention.Furthermore, some of the crystalline forms for the compounds may existas polymorphs and as such are intended to be included in the presentinvention. In addition, some of the compounds may form solvates withwater (i.e., hydrates) or common organic solvents, and such solvates arealso intended to be encompassed within the scope of this invention.

As used herein, unless otherwise noted, “halogen” shall mean chlorine,bromine, fluorine and iodine.

The term “alkyl”, whether used alone or as part of a substituent group,shall mean straight or branched chain alkanes of one to ten carbonatoms, or any number within this range. For example, alkyl radicalsinclude, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, t-butyl, n-pentyl, 3-(2-methyl)butyl, 2-pentyl,2-methylbutyl, neopentyl, n-hexyl and 2-methylpentyl.

The term “alkoxy” shall denote an oxygen ether radical of the abovedescribed straight or branched chain alkyl group. For example, alkoxyradicals include methoxy, ethoxy, n-propoxy, n-butoxy, sec-butoxy,tert-butoxy, and the like.

The term “aryl” indicates an aromatic groups such as phenyl, naphthyl,and the like.

The term “aralkyl” denotes an alkyl group substituted with an arylgroup. For example, benzyl, phenylethyl, and the like.

The term “heteroaryl” as used herein represents a stable five or sixmembered monocyclic aromatic ring system containing one to threeheteroatoms independently selected from N, O or S; and any nine or tenmembered bicyclic aromatic ring system containing carbon atoms and oneto four heteroatoms independently selected from N, O or S. Theheteroaryl group may be attached at any heteroatom or carbon atom whichresults in the creation of a stable structure. Examples of heteroarylgroups include, but are not limited to pyridyl, pyrimidinyl, thienyl,furyl, imidazolyl, isoxazolyl, oxazolyl, pyrazolyl, pyrazinyl, pyrrolyl,thiazolyl, thiadiazolyl, triazolyl, benzimidazolyl, benzofuranyl,benzothienyl, benzisoxazolyl, benzoxazolyl, indazolyl, indolyl,benzothiazolyl, benzothiadiazolyl, benzotriazolyl, quinolinyl orisoquinolinyl. Particularly preferred heteroaryl groups include pyridyl,pyrazolyl, furyl, thiazolyl, thienyl, imidazolyl, isoxazolyl, pyrazinyl,pyrimidinyl, triazolyl, benzofuryl, benzothienyl, benzimidazolyl,benzothiazolyl and benzoxazolyl.

The term “cycloalkyl” as used herein represents a stable three to eightmembered monocyclic ring structure consisting of saturated carbon atoms.Suitable examples include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl and cyclooctyl.

The term “heterocycloalkyl” represents a stable saturated or partiallyunsaturated, three to eight membered monocyclic ring structurecontaining carbon atoms and one to four, preferably one to two,heteroatoms independently selected from N, O or S; and any stablesaturated, partially unsaturated or partially aromatic, nine to tenmembered bicyclic ring system containing carbon atoms and one to fourheteroatoms independently selected from N, O or S. The heterocycloalkylmay be attached at any carbon atom or heteroatom which results in thecreation of a stable structure. Suitable examples of heterocycloalkylgroups include pyrrolidinyl, pyrazolidinyl, piperidinyl, piperazinyl,morpholinyl, dithianyl, trithianyl, dioxolanyl, dioxanyl,thiomorpholinyl, 3,4-methylenedioxyphenyl, 2,3-dihydrobenzofuryl,2,3-dihydrobenzo-[1,4]-dioxin-6-yl, 2,3-dihydro-furo[2,3-b]pyridyl,1,2-(methylenedioxy)cyclohexane, and the like. Particularly preferredheterocycloalkyl groups include pyrrolidinyl, morpholinyl,3,4-methylenedioxyphenyl, 2,3-dihydrobenzofuryl and2,3-dihydrobenzo-[1,4]-dioxin-6-yl.

As used herein, the notation “*” shall denote the presence of astereogenic center.

Under standard nomenclature used throughout this disclosure, theterminal portion of the designated side chain is described first,followed by the adjacent functionality toward the point of attachment.Thus, for example, a “phenylC₁-C₆ alkylaminocarbonylC₁-C₆alkyl”substituent refers to a group of the formula

It is intended that the definition of any substituent or variable at aparticular location in a molecule be independent of its definitionselsewhere in that molecule. It is understood that substituents andsubstitution patterns on the compounds of this invention can be selectedby one of ordinary skill in the art to provide compounds that arechemically stable and that can be readily synthesized by techniquesknown in the art as well as those methods set forth herein. It isfurther intended that when n or m is >1, the corresponding R¹ or R³substituents may be the same or different.

The term “sexual dysfunction” as used herein, includes male sexualdysfunction, male erectile dysfunction, impotence, female sexualdysfunction, female sexual arousal dysfunction and female sexualdysfunction related to blood flow and nitric oxide production in thetissues of the vagina and clitoris.

The term “subject” as used herein, refers to an animal, preferably amammal, most preferably a human, who has been the object of treatment,observation or experiment.

The term “therapeutically effective amount” as used herein, means thatamount of active compound or pharmaceutical agent that elicits thebiological or medicinal response in a tissue system, animal or humanthat is being sought by a researcher, veterinarian, medical doctor orother clinician, which includes alleviation of the symptoms of thedisease or disorder being treated.

As used herein, the term “composition” is intended to encompass aproduct comprising the specified ingredients in the specified amounts,as well as any product which results, directly or indirectly, fromcombinations of the specified ingredients in the specified amounts.

Abbreviations used in the specification, particularly the Reactions andExamples, are as follows:

Cmpd # = Compound ID Number DCC = 1,3-Dicyclohexylcarbodiimide DCM =Dichloromethane DDQ = Dichlorodicyanoquinone DIC =Diisopropylcarbodiimide DIPEA = Diisopropylethylamine DMF =N,N-Dimethylformamide DMSO = Dimethylsulfoxide dppp =1,3-Bis(diphenylphosphino) propane EDTA = Ethylenedinitrilotetraceticacid Fmoc = 9-Fluorenylmethoxycarbonyl Fmoc-NCS =9-fluorenylmethoxycarbonyl isothiocyanate HEPES =2-[4-(2-Hydroxyethyl)-piperazinyl]- ethanesulfonic acid LAH = LithiumAluminum Hydride PDE = Phosphodiesterase Pd₂dba₃ = Tris(dibenzylideneacetone) dipalladium (0) Pd(OAc)₂ = Palladium (II) Acetate Pd(PPh₃)₄Palladium tetrakis(triphenyl phosphine) Ph = Phenyl PMSF = Phenylmethanesulfonyl fluoride PPh₃ Triphenyl phosphine PyBop =(1-Hydroxy-1H-benzotriazolato-O)tri- 1-pyrrolidinyl phosphorous PyBrop =Bromo-tri-1-pyrridinyl phosphorous SNP = Sodium nitroprusside TEA =Triethylamine TFA = Trifluoroacetic acid THF = Tetrahydrofuran TsOH =Tosic Acid

Compounds of formula (I) may be prepared according to the processesoutlined in more detail below.

Compounds of formula (I) wherein (Y)_(a) is C(O) may be preparedaccording to a process as outlined in Scheme 1.

More particularly, a compound of formula (II), wherein X is O, S or NH,a known compound or compound produced by known methods, is reacted witha suitably substituted aldehyde of formula (III), in an organic solventsuch as DCM, THF, toluene, and the like, in the presence of an acidcatalyst such as TFA, tosic acid, and the like, to produce thecorresponding tricyclic compound of formula (IV).

The compound of formula (IV) is reacted with a suitably substitutedcompound of formula (V), wherein A is halogen, in the presence of a basesuch as triethylamine (TEA), diisopropylethylamine (DIPEA), sodiumcarbonate and the like, in an organic solvent such as dichloromethane(DCM), N,N′-dimethylformamide (DMF), tetrahydrofuran (THF), and thelike; or with a suitably substituted compound of formula (V), wherein Ais hydroxy, in the presence of a coupling agent such as DCC, DIC, PyBop,PyBrop, and the like, in an organic solvent such as dichloromethane(DCM), N,N′-dimethylformamide (DMF), tetrahydrofuran (THF), and thelike; to produce the corresponding compound of formula (Ia).

Alternatively, compounds of formula (I), wherein X is O, S, or NH and(Y)_(a) is C(O) may be prepared according to a process as outlined inScheme 2.

More particularly, a compound of formula (II), wherein X is O, S or NH,is reacted with a suitably substituted compound of formula (VI), whereinA is halogen or hydroxy, in an organic solvent such as DCM, THF, DMF,and the like, to produce the corresponding compound of formula (VII).

The compound of formula (VII) is cyclized by treatment with POCl₃, in anorganic solvent such as toluene, benzene, and the like, followed byreduction with NaBH₄, in an organic solvent such as ethanol,isopropanol, and the like, to produce the corresponding compound offormula (IV).

The compound of formula (IV) is then reacted with a suitably substitutedcompound of formula (V) to produce the compound of formula (Ia) asoutlined in Scheme 1.

Compounds of formula (I), wherein X is O, S or NH and (Y)_(a) is SO₂ maybe prepared according to a process as outlined in Scheme 3.

Accordingly, a suitably substituted compound of formula (IV) is reactedwith a suitably substituted compound of formula (VIII), wherein A ishalogen or hydroxy, a known compound or compound prepared by knownmethods, in an organic solvent such as DCM, chloroform, DMF, THF, andthe like, to produce the corresponding compound of formula (Ib).

Compounds of formula (I) wherein X is O, S or NH and (Y)_(a) is CH₂ maybe prepared according to a process as outlined in Scheme 4.

Accordingly, a suitably substituted compound of formula (Ia) is treatedwith a reducing agent such as LAH, diboron, and the like, preferablyLAH, in an organic solvent such as methanol, THF, diethyl ether, and thelike, preferably at a temperature in the range of about −20 to 40° C.,to produce the corresponding compound of formula (Ic).

Compounds of formula (I) wherein (Y)_(a) is CH₂ and X is NH, mayalternatively be prepared according to a process as outlined in Scheme5.

Accordingly, a compound of formula (IVa) is reacted with a suitablysubstituted compound of formula (IX), wherein Q is halogen, O-tosylateor O-mesolate, in an organic solvent such as DCM, THF, and the like, toproduce the corresponding compound of formula (Id).

Compounds of formula (I), wherein X is O, S or NH and (Y)_(a) is (Y)₀(i.e. wherein a is 0, such that Y is absent), may be prepared accordingto a process as outlined in Scheme 6.

More specifically, a compound of formula (IV), a known compound orcompound produced by known methods, is reacted with a suitablysubstituted halide of formula (X), a known compound or compound preparedby known methods, in an organic solvent such as toluene, DMF,1-methyl-2-pyrrolidinone, and the like, preferably at a temperature inthe range of about 80 to 250° C., to produce the corresponding compoundof formula (Ie).

Compounds of formula (I) wherein X is NR^(D) may be prepared byaccording to a process as outlined in Scheme 7.

Accordingly, a compound of formula (If) is reacted with a compound offormula (XI), wherein Z is halogen, hydroxy, O-toylate or O-mesolate anda base such as sodium hydride, potassium t-butoxide, and the like, in asolvent such DMF, 1-methyl-2-pyrrolidinone, and the like, to produce thecorresponding compound of formula (Ig).

Compounds of formula (I) wherein Z is CH—OH or C(O) may be preparedaccording to a process as outlined in Scheme 8.

More particularly, a compound of formula (If) is treated with anoxidizing agent such as DDQ, chloranil, and the like, in a solvent suchas THF, methanol, water, and the like, preferably at a temperature inthe range of about −78 to about 30° C., to produce a mixture of thecorresponding compounds of formula (Ih) and (Ii). Preferably, thecompounds of formula (Ih) and (Ii) are separated by known methods, suchas recrystallization, column chromatography, and the like.

Compounds of formula (I) wherein

is 2-thiazolyl, may be prepared according to a process as outlined inScheme 9.

Accordingly, a suitably substituted compound of formula (IVa) is reactedwith Fmoc-NCS, in an organic solvent such as DCM, DMF, THF, and thelike, preferably at room temperature, to produce the correspondingcompound of formula (XII).

The compound of (XII) is reacted with 20% piperidine, in an alcohol suchas methanol, ethanol, and the like, to produce the corresponding amineof formula (XIII).

The amine of formula (XIII) is reacted with a suitably substitutedα-halo methyl ketone of formula (XIV), in the presence of an organicsolvent or mixture such as DMF, ethanol:dioxane, and the like, in thepresence of a base such as TEA, DIPEA, and the like, preferably at atemperature of about 70° C., to produce the corresponding compound offormula (Ij).

Compounds of formula (I) wherein (Y)_(a) is C(O)O, may be preparedaccording to the process outlined in Scheme 10.

More particularly, a compound of formula (IV) is reacted with a suitablysubstituted chloroformate of formula (XV) or an anhydride of formula(XVI) in an organic solvent such as DCM, DMF, THF, and the like, toproduce the corresponding compound of formula (Ik).

Compounds of formula (I) wherein (Y)_(a) is C(O)—NH may be preparedaccording to a process as outlined in Scheme 11.

Accordingly, a compound of formula (IV) is reacted with a suitablysubstituted compound of formula (XVII), in an organic solvent such asDCM, DMF, THF, and the like, to produce the corresponding compound offormula (Im).

Where the processes for the preparation of the compounds according tothe invention give rise to mixture of stereoisomers, these isomers maybe separated by conventional techniques such as preparativechromatography. The compounds may be prepared in racemic form, orindividual enantiomers may be prepared either by enantiospecificsynthesis or by resolution. The compounds may, for example, be resolvedinto their component enantiomers by standard techniques, such as theformation of diastereomeric pairs by salt formation with an opticallyactive acid, such as (−)-di-p-toluoyl-d-tartaric acid and/or(+)-di-p-toluoyl-l-tartaric acid followed by fractional crystallizationand regeneration of the free base. The compounds may also be resolved byformation of diastereomeric esters or amides, followed bychromatographic separation and removal of the chiral auxiliary.Alternatively, the compounds may be resolved using a chiral HPLC column.

During any of the processes for preparation of the compounds of thepresent invention, it may be necessary and/or desirable to protectsensitive or reactive groups on any of the molecules concerned. This maybe achieved by means of conventional protecting groups, such as thosedescribed in Protective Groups in Organic Chemistry, ed. J. F. W.McOmie, Plenum Press, 1973; and T. W. Greene & P. G. M. Wuts, ProtectiveGroups in Organic Synthesis, John Wiley & Sons, 1991. The protectinggroups may be removed at a convenient subsequent stage using methodsknown from the art.

The utility of the compounds to treat sexual dysfunction can bedetermined according to the procedures described in Example 10, 11 and12 herein.

The present invention therefore provides a method of treating sexualdysfunction in a subject in need thereof, which comprises administeringany of the compounds as defined herein in a quantity effective to treatsexual dysfunction. The compound may be administered to a patient by anyconventional route of administration, including, but not limited to,intravenous, oral, subcutaneous, intramuscular, intradermal andparenteral. The quantity of the compound which is effective for treatingsexual dysfunction is between 0.1 mg per kg and 20 mg per kg of subjectbody weight.

The present invention also provides pharmaceutical compositionscomprising one or more compounds of this invention in association with apharmaceutically acceptable carrier. Preferably these compositions arein unit dosage forms such as tablets, pills, capsules, powders,granules, sterile parenteral solutions or suspensions, metered aerosolor liquid sprays, drops, ampoules, autoinjector devices orsuppositories; for oral parenteral, intranasal, sublingual or rectaladministration, or for administration by inhalation or insufflation.Alternatively, the composition may be presented in a form suitable foronce-weekly or once-monthly administration; for example, an insolublesalt of the active compound, such as the decanoate salt, may be adaptedto provide a depot preparation for intramuscular injection. Forpreparing solid compositions such as tablets, the principal activeingredient is mixed with a pharmaceutical carrier, e.g. conventionaltableting ingredients such as corn starch, lactose, sucrose, sorbitol,talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, andother pharmaceutical diluents, e.g. water, to form a solidpreformulation composition containing a homogeneous mixture of acompound of the present invention, or a pharmaceutically acceptable saltthereof. When referring to these preformulation compositions ashomogeneous, it is meant that the active ingredient is dispersed evenlythroughout the composition so that the composition may be readilysubdivided into equally effective dosage forms such as tablets, pillsand capsules. This solid preformulation composition is then subdividedinto unit dosage forms of the type described above containing from 1 toabout 1000 mg of the active ingredient of the present invention. Thetablets or pills of the novel composition can be coated or otherwisecompounded to provide a dosage form affording the advantage of prolongedaction. For example, the tablet or pill can comprise an inner dosage andan outer dosage component, the latter being in the form of an envelopeover the former. The two components can be separated by an enteric layerwhich serves to resist disintegration in the stomach and permits theinner component to pass intact into the duodenum or to be delayed inrelease. A variety of material can be used for such enteric layers orcoatings, such materials including a number of polymeric acids with suchmaterials as shellac, cetyl alcohol and cellulose acetate.

The liquid forms in which the novel compositions of the presentinvention may be incorporated for administration orally or by injectioninclude, aqueous solutions, suitably flavoured syrups, aqueous or oilsuspensions, and flavoured emulsions with edible oils such as cottonseedoil, sesame oil, coconut oil or peanut oil, as well as elixirs andsimilar pharmaceutical vehicles. Suitable dispersing or suspendingagents for aqueous suspensions, include synthetic and natural gums suchas tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose,methylcellulose, polyvinylpyrrolidone or gelatin.

The method of treating sexual dysfunction, particularly male erectiledysfunction (ED) described in the present invention may also be carriedout using a pharmaceutical composition comprising any of the compoundsas defined herein and a pharmaceutically acceptable carrier. Thepharmaceutical composition may contain between about 1 mg and 1000 mg,preferably about 10 to 500 mg, of the compound, and may be constitutedinto any form suitable for the mode of administration selected. Carriersinclude necessary and inert pharmaceutical excipients, including, butnot limited to, binders, suspending agents, lubricants, flavorants,sweeteners, preservatives, dyes, and coatings. Compositions suitable fororal administration include solid forms, such as pills, tablets,caplets, capsules (each including immediate release, timed release andsustained release formulations), granules, and powders, and liquidforms, such as solutions, syrups, elixers, emulsions, and suspensions.Forms useful for parenteral administration include sterile solutions,emulsions and suspensions.

Advantageously, compounds of the present invention may be administeredin a single daily dose, or the total daily dosage may be administered individed doses of two, three or four times daily. Furthermore, compoundsfor the present invention can be administered in intranasal form viatopical use of suitable intranasal vehicles, or via transdermal skinpatches well known to those of ordinary skill in that art. To beadministered in the form of a transdermal delivery system, the dosageadministration will, of course, be continuous rather than intermittentthroughout the dosage regimen.

For instance, for oral administration in the form of a tablet orcapsule, the active drug component can be combined with an oral,non-toxic pharmaceutically acceptable inert carrier such as ethanol,glycerol, water and the like. Moreover, when desired or necessary,suitable binders, lubricants, disintegrating agents and coloring agentscan also be incorporated into the mixture. Suitable binders include,without limitation, starch, gelatin, natural sugars such as glucose orbeta-lactose, corn sweeteners, natural and synthetic gums such asacacia, tragacanth or sodium oleate, sodium stearate, magnesiumstearate, sodium benzoate, sodium acetate, sodium chloride and the like.Disintegrators include, without limitation, starch, methyl cellulose,agar, bentonite, xanthan gum and the like.

The liquid forms may include suitably flavored suspending or dispersingagents such as the synthetic and natural gums, for example, tragacanth,acacia, methyl-cellulose and the like. For parenteral administration,sterile suspensions and solutions are desired. Isotonic preparationswhich generally contain suitable preservatives are employed whenintravenous administration is desired.

The compound of the present invention can also be administered in theform of liposome delivery systems, such as small unilamellar vesicles,large unilamellar vesicles, and multilamellar vesicles. Liposomes can beformed from a variety of phospholipids, such as cholesterol,stearylamine or phophatidylcholines.

Compounds of the present invention may also be delivered by the use ofmonoclonal antibodies as individual carriers to which the compoundmolecules are coupled. The compounds of the present invention may alsobe coupled with soluble polymers as targetable drug carriers. Suchpolymers can include polyvinylpyrrolidone, pyran copolymer,polyhydroxypropylmethacrylamidephenol,polyhydroxyethylaspartamidephenol, or polyethyl-eneoxidepolylysinesubstituted with palmitoyl residue. Furthermore, the compounds of thepresent invention may be coupled to a class of biodegradable polymersuseful in achieving controlled release of a drug, for example,polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid,polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates andcross-linked or amphipathic block copolymers of hydrogels.

Compounds of this invention may be administered in any of the foregoingcompositions and according to dosage regimens established in the artwhenever treatment of sexual dysfunction, particularly male erectiledysfunction (ED) is required.

The daily dosage of the products may be varied over a wide range from 1to 1,000 mg per adult human per day. For oral administration, thecompositions are preferably provided in the form of tablets containing,5.0, 10.0, 15.0, 25.0, 50.0, 100, 250 and 500 milligrams of the activeingredient for the symptomatic adjustment of the dosage to the patientto be treated. An effective amount of the drug is ordinarily supplied ata dosage level of from about 0.1 mg/kg to about 20 mg/kg of body weightper day. Preferably, the range is from about 0.2 mg/kg to about 10 mg/kgof body weight per day, and especially from about 0.5 mg/kg to about 10mg/kg of body weight per day. The compounds may be administered on aregimen of 1 to 4 times per day.

Optimal dosages to be administered may be readily determined by thoseskilled in the art, and will vary with the particular compound used, themode of administration, the strength of the preparation, the mode ofadministration, and the advancement of the disease condition. Inaddition, factors associated with the particular patient being treated,including patient age, weight, diet and time of administration, willresult in the need to adjust dosages.

The following Examples are set forth to aid in the understanding of theinvention, and are not intended and should not be construed to limit inany way the invention set forth in the claims which follow thereafter.

Unless otherwise indicated, ¹H NMRs were run on a Bruker AC-300.

EXAMPLE 11-(3,4-Methylenedioxyphenyl)-2-[5-(3-trifluoromethylphenyl)furoyl]-2,3,4,9-tetrahydro-1H-β-carboline(#58)

To a suspension of 5-(3-trifluoromethylphenyl)furoic acid (256 mg, 1mmol) in DCM (20 mL, anhydrous) was added oxalyl chloride (165 mg, 1.3mmol), followed by two drops of DMF. The mixture was stirred at roomtemperature for 1 h. A solution of1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahydro-1H-β-carboline (292 mg,1 mmol) (prepared according to the process as disclosed in WO97/43287,Intermediate 7, page 24) and triethylamine (0.4 mL) in DCM (10 mL,anhydrous) was added and the mixture was stirred at room temperature for16 h, washed sequentially with aqueous NaHCO₃, brine (2×), 1N HCl andbrine (2×) and dried with MgSO₄. After evaporation of the solvent, awhite solid was obtained.

mp: 126-129° C.

MS (m/z): 531 (MH⁺);

¹H-NMR (CDCl₃) δ2.96 (d, J=8 Hz, 1 H), 3.24 (m, 1 H), 3.56 (m, 1 H),4.60 (d, J=8 Hz, 1 H), 5.90 (s, 2 H), 6.70 (d, J=8 Hz, 1 H), 6.83-6.99(m, 4 H), 7.13-7.34 (m, 4 H), 7.55 (m, 3 H), 7.87 (d, J=7 Hz, 1 H), 7.95(s, 1 H), 8.23 (s, 1 H);

EXAMPLE 29-[2-(Pyrrolidin-1-yl)-ethyl]-1-(3,4-methylenedioxyphenyl)-2-[5-(3-trifluoromethylphenyl)furoyl]-2,3,4-trihydro-1H-β-carboline(#75)

To a solution of 1-(3,4-methylenedioxyphenyl)-2-[5-(3-trifluoromethylphenyl)furoyl]-2,3,4,9-tetrahydro-1H-β-carboline (prepared as inExample 1) (600 mg, 1.14 mmol) in DMF (15 mL, anhydrous) was addedsodium hydride (60%, 105 mg, 2.6 mmol) at room temperature. The mixturewas stirred at room temperature for 30 min. N-chloroethylpyrrolidinehydrochloride (214 mg, 1.26 mmol) and 15-crown ether-5 (1 drop) wereadded. The mixture was stirred at room temperature for 16 h, quenchedwith NH₄Cl, extracted with ethyl acetate and dried with MgSO₄. Afterevaporation of the solvent, the residue was purified by columnchromatography (silica gel, ethyl acetate:hexanes=3:1) to yield a whitesolid.

MS (m/z): 628 (MH⁺)

¹H-NMR (CDCl₃) δ1.26 (m, 4 H), 2.64 (m, 4 H), 2.89 (m, 2 H), 3.05 (d,J=8 Hz, 1 H), 3.28 (t, J=8 Hz, 1 H), 3.59 (t, J=8 Hz, 1 H), 3.96 (m, 1H), 4.16 (m, 1 H), 4.58 (d, J=8 Hz, 1 H), 5.96 (s, 2 H), 6.75 (d, J=8Hz, 1 H), 6.84 (m, 2 H), 7.02 (d, J=8 Hz, 1 H), 7.15-7.29 (m, 4 H), 7.43(s, 1 H), 7.59 (m, 3 H), 7.89 (d, J=7 Hz, 1 H), 7.96 (s, 1 H)

The corresponding methanesulfonic acid salt was prepared by addition of1.0 equivalent of methanesulfonic acid to a solution of the titlecompound in DCM to produce product for biological testing.

mp: 122-124° C.

EXAMPLE 31-(3,4-Methylenedioxyphenyl)-2-[5-(3,4-dimethoxyphenyl)pyrimidin-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(#7)

A solution of1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahydro-1H-β-carboline (3.73 g,12.8 mmol) (prepared according to the process as disclosed inWO97/43287. Intermediate 7, page 24) and2-chloro-5-(3,4-dimethoxyphenyl)pyrimidine (1.6 g, 6.4 mmol) in DMF (50mL, anhydrous) was heated at 120° C. under stirring for 16 h. Thereaction mixture was quenched with NH₄Cl and extracted with ethylacetate. The organic phase was washed with brine (2×) and dried withMgSO₄. Column chromatography (silica gel, ethyl acetate:hexanes=2:3)yielded a white solid.

mp: 173-175° C.

MS (m/z): 507 (MH⁺)

¹H-NMR (CDCl₃) δ2.91 (d, J=9 Hz, 1 H), 3.02 (td, J=9, 1 Hz, 1 H), 3.39(td, J=9, 1 Hz, 1 H), 3.92 (s, 3 H), 3.94 (s, 3 H), 5.02 (d, J=9, 1 Hz,1 H), 5.92 (s, 2 H), 6.72 (d, J=8 Hz, 1 H), 6.87-7.03 (m, 4 H),7.11-7.17 (m, 3 H), 7.31 (d, J=8 Hz, 1 H), 7.56 (d, J=8 Hz, 1 H), 7.80(s, 1 H), 8.56 (s, 2 H)

EXAMPLE 41-(3,4-Methylenedioxyphenyl)-2-[5-(3,4-dimethoxyphenyl)pyrimidin-2-yl]-9-dimethylaminoethyl-2,3,4-trihydro-1H-β-carboline(#5)

Following the procedure outlined in Example2,1-(3,4-methylenedioxyphenyl)-2-[5-(3,4-dimethoxyphenyl)pyrimidin-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(prepared as in Example 3) (1.0 g, 1.97 mmol),2-chloro-N,N-dimethylethylamine hydrochloride (0.342 g, 2.37 mmol),sodium hydride (60%, 0.190 g, 4.74 mmol) and 15-crown ether-5 werereacted to yield the product as a slightly yellow solid (after columnchromatography with silica gel, ethyl acetate).

MS (m/z): 578 (MH⁺)

¹H-NMR (CDCl₃) δ2.21 (s, 6 H), 2.22 (m, 1 H), 2.61 (m, 1 H), 2.89 (dd,J=13, 4 Hz, 1 H), 3.03 (td, J=13, 4 Hz, 1 H), 3.35 (td, J=13, 4 Hz, 1H), 3.91 (m, 1 H), 3.92 (s, 3 H), 3.95 (s, 3 H), 4.06 (m, 1 H), 4.96(dd, J=13, 4 Hz, 1 H), 5.93 (s, 2 H), 6.72 (d, J=8 Hz, 1 H), 6.83 (d, 1H), 6.85-6.98 (m, 4 H), 7.12 (d, J=8 Hz, 1 H), 7.21 (d, J=8 Hz, 1 H),7.31 (d, J=8 Hz, 1 H), 7.34 (s, 1 H), 7.58 (d, J=8 Hz, 1 H), 8.56 (s, 2H)

EXAMPLE 51-(3,4-Methylenedioxyphenyl)-2-[5-(4-methoxyphenyl)-pyrimidin-2-yl]-4-oxo-2,3,4,9-tetrahydro-1H-β-carboline(#157) &1-(3,4-Methylenedioxy-phenyl)-2-[5-(4-methoxyphenyl)-pyrimidin-2-yl]-4-hydoxy-2,3,4,9-tetrahydro-1H-β-carboline(#158)

To a mixture of DDQ (113.5 mg, 0.5 mmol) and1-(3,4-methylenedioxyphenyl)-2-[5-(3,4-dimethoxyphenyl)pyrimidin-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(prepared as in Example 3) (51 mg, 0.1 mmol) was added a mixed solventof THF:water (9:1) at −78° C. The mixture was stirred at 0° C. andallowed to warm to room temperature over a period of 15 h. Columnchromatography (silica gel, hexanes:ethyl acetate=1:1) yielded the -oxo-and -hydroxy derivatives respectively, as white solids.

#157:

MS (m/z) 521 (MH⁺), 519 (M-1)

¹H NMR (CDCl₃) δ3.90 (d, J=18 Hz, 1 H), 3.89 (s, 3 H), 3.91 (s, 3 H),5.43 (d, J=18 Hz, 1 H), 5.84 (s, 2 H), 6.62 (d, J=8 Hz, 1 H), 6.71 (d,J=8 Hz, 1 H), 6.88-7.00 (m, 4 H), 7.29-7.43 (m, 3 H), 7.53 (s, 1 H),8.25 (m, 1 H), 8.51 (s, 2 H); 9.55 (s, 1 H)

#158:

MS (m/z) 523 (MH⁺), 521 (M-1)

¹H NMR (CDCl₃) δ3.30 (t, J=6 Hz, 1 H), 3.69 (d, J=6 Hz, 1 H), 3.92 (s, 3H), 3.94 (s, 3 H), 5.97 (s, 2 H), 6.11 (s, 1 H), 6.71 (d, J=8 Hz, 1 H),6.93-7.05 (m, 4 H), 7.18 (d, J=8 Hz, 1 H), 7.23 (d, J=8 Hz, 1 H), 7.40(t, J=6 Hz, 1 H), 7.49 (d, J=8 Hz, 1 H), 7.82 (d, J=8 Hz, 1 H), 8.43 (s,2 H); 9.15 (s, 1 H)

EXAMPLE 61-(3,4-Methylenedioxyphenyl)-2-[4-(4-methoxyphenyl)thiazol-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(#169)

A. 1-(3,4-Methylenedioxyphenyl)-2-[3-(fluorenylmethyloxycarbonyl)Thiocarbamoyl]-2,3,4,9-tetrahydro-1H-β-carboline

A mixture of1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahydro-1H-β-carboline (2.66 g,9.08 mmol) (prepared according to the process as disclosed inWO97/43287, Intermediate 7, page 24) and Fmoc-isothiocyanate (2.82 g,10.14 mmol) was dissolved in dry dichloromethane (50 mL). The mixturewas stirred for 16 hours at ambient temperature, and then concentratedin vacuo. Purification by flash chromatography (0-10% methanol indichloromethane) yielded the protected thiourea as a pale yellow solid.

MS (m/z): 574 (MH⁺)

¹H-NMR (CDCl₃) δ2.86 (dd, J=12.9, 5.1 Hz, 1 H), 3.09 (dt, J=17.1, 6.9Hz, 1 H), 3.56 (dt, J=12.9, 5.1 Hz, 1 H), 4.19 (t, J=6.9 Hz, 1 H),4.43-4.53 (m, 2 H), 5.91 (s, 2 H), 6.70 (d, J=8 Hz, 1 H), 6.90 (br d,J=7.6 Hz, 1 H), 6.97 (br s, 1 H), 7.11-7.78 (series of m, 17 H)

B.1-(3,4-Methylenedioxyphenyl)-2-(thiocarbamoyl)-2,3,4,9-tetrahydro-1H-β-carboline

A solution of the protected thiourea from Part A (4.78 g, 8.33 mmol) in20% (v/v) piperidine in methanol was heated to reflux for 5 h. Themixture was concentrated in vacuo to yield a crude residue which waspurified by flash chromatography (SiO₂, 0-10% methanol indichloromethane) to yield a yellow solid.

MS (m/z): 352 (MH⁺)

¹H-NMR (CDCl₃) δ2.69-2.87 (series of m, 2 H), 3.10-3.19 (m, 1 H), 4.24(br s, 1 H), 6.00 (d, J=3.3 Hz, 2 H), 6.72 (d, J=8.0 Hz, 1 H), 6.87 (d,J=8.0 Hz, 1H), 7.00-7.11 (series of m, 3 H), 7.30 (d, J=8.0 Hz, 1 H),7.46 (d, J=7.7 Hz, 1H), 7.74 (br s, 3 H), 11.06 (s, 1 H)

C.1-(3,4-Methylenedioxyphenyl)-2-[4-(4-methoxyphenyl)thiazol-2yl]-2,3,4,9-tetrahydro-1H-β-carboline(#169)

To a solution of the thiourea from Part B (223 mg, 0.63 mmol) in a 1:1mixture of dioxane:ethanol (5 mL) was added4-methoxyphenyl-2′-bromoacetophenone (175 mg, 0.76 mmol) andtriethylamine (0.40 mL). The mixture was heated to 70° C. for 3 h,cooled to room temperature and concentrated in a rotary evaporator. Theresidue was purified by flash chromatography (SiO₂, 0-10% methanol indichloromethane) to yield a colorless solid.

MS (m/z): 482 (MH⁺)

¹H-NMR (CDCl₃) δ2.86-2-3.07 (series of m, 2 H), 3.61-3.71 (m, 1 H), 3.78(s, 3 H), 3.91-4.02 (m, 1 H), 5.99 (d, J=3.3 Hz, 2 H), 6.58 (s, 1 H),6.80-7.11 (series of m, 8 H), 7.31 (d, J=7.8 Hz, 1 H), 7.48 (d, J=7.6Hz, 1 H), 7.82 (d, J=8.7 Hz, 2 H), 10.93 (s, 1 H)

EXAMPLE 71-(3,4-Methylenedioxyphenyl)-2-[4-phenylthiazol-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(#170)

A. 1-(3,4-Methylenedioxyphenyl)-2-[3-(fluorenylmethyloxycarbonyl)thiocarbamoyl]-2,3,4,9-tetrahydro-1H-β-carboline

A mixture of1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahydro-1H-β-carboline (2.66 g,9.08 mmol) (prepared according to the process as disclosed inWO97/43287, Intermediate 7, page 24) and Fmoc-isothiocyanate (2.82 g,10.14 mmol) was dissolved in dry dichloromethane (50 mL). The mixturewas stirred for 16 hours at ambient temperature, and then concentratedin vacuo. Purification by flash chromatography (0-10% methanol indichloromethane) yielded the protected thiourea as a pale yellow solid.

MS (m/z): 574 (MH⁺)

¹H-NMR (CDCl₃) δ2.86 (dd, J=12.9, 5.1 Hz, 1 H), 3.09 (dt, J=17.1, 6.9Hz, 1 H), 3.56 (dt, J=12.9, 5.1 Hz, 1 H), 4.19 (t, J=6.9 Hz, 1 H),4.43-4.53 (m, 2 H), 5.91 (s, 2 H), 6.70 (d, J=8 Hz, 1 H), 6.90 (br d,J=7.6 Hz, 1 H), 6.97 (br s, 1 H), 7.11-7.78 (series of m, 17 H)

B.1-(3,4-Methylenedioxyphenyl)-2-(thiocarbamoyl)-2,3,4,9-tetrahydro-1H-β-carboline

A solution of the protected thiourea from Part A (4.78 g, 8.33 mmol) in20% (v/v) piperidine in methanol was heated to reflux for 5 h. Themixture was concentrated in vacuo to yield a crude residue which waspurified by flash chromatography (SiO₂, 0-10% methanol indichloromethane) to yield a yellow solid.

MS (m/z): 352 (MH⁺)

¹H-NMR (CDCl₃) δ2.69-2.87 (series of m, 2 H), 3.10-3.19 (m, 1 H), 4.24(br s, 1 H), 6.00 (d, J=3.3 Hz, 2 H), 6.72 (d, J=8.0 Hz, 1 H), 6.87 (d,J=8.0 Hz, 1H), 7.00-7.11 (series of m, 3 H), 7.30 (d, J=8.0 Hz, 1 H),7.46 (d, J=7.7 Hz, 1H), 7.74 (br s, 3 H), 11.06 (s, 1 H)

C.1-(3,4-Methylenedioxyphenyl)-2-[4-phenylthiazol-2yl]-2,3,4,9-tetrahydro-1H-β-carboline(#170)

To a solution of the thiourea of Part B (227 mg, 0.65 mmol) was addedβ-bromoacetophenone (159 mg, 0.80 mmol) and triethylamine (0.40 mL).This mixture was heated to 70° C. for 3 h, cooled to room temperatureand concentrated in a rotary evaporator. The residue was purified byflash chromatography (SiO₂, 0-10% methanol in dichloromethane) to yielda pale yellow solid.

MS (m/z): 452 (MH⁺)

¹H-NMR (CDCl₃) δ2.87-2-3.06 (series of m, 2 H), 3.63-3.73 (m, 1 H),3.93-3.99 (m, 1 H), 5.99 (d, J=3.3 Hz, 2 H), 6.59 (s, 1 H), 6.81-7.11(series of m, 5 H), 7.25-7.69 (series of m, 6 H), 7.89 (d, J=7.4 Hz, 2H), 10.95 (s, 1 H)

EXAMPLE 81-(2,3-Dihydro-benzofuran-5-yl)-2-[5-(2,3-dimethyl-3H-imidazol-4-yl)-pyrimidin-2-yl]-2,3,4,9-tetrahydro-1H-β-carboline(#190)

2-(5-bromo-2-pyrimidinyl)-1-(2,3-dihydro-5-benzofuranyl)-2,3,4,9-tetrahydro-1H-β-carboline(0.45 g, 1.00 mmol), 1,2-dimethyl-1H-imidazole (0.18 g, 1.87 mmol),Pd(OAc)₂ (12 mg, 0.05 mmol), PPh₃ (26 mg, 0.1 mmol) and K₂CO₃ (0.28 g, 2mmol) were stirred in 3.5 mL DMF at 140° C. for 14 hours. The mixturewas poured into aqueous 10% NaOH solution (50 mL). The resultingsolution was extracted with CH₂Cl₂ (3×50 mL) and dried over Na₂SO₄.Purification by preparative TLC yielded the title product as yellowpowder.

¹H NMR 300 MHz (CDCl₃) δ2.21 (s, 3H), 2.35 (s, 3H), 2.90 (m, 2H), 3.10(t, 2H, J=8.8. Hz), 3.35 (m, 1H), 4.52 (t, 2H, J=8.8. Hz), 4.91 (m, 1H),6.68˜7.61 (m, 10 H)

MS (m/z) 463 (MH⁺), 461 (MH⁻).

EXAMPLE 92-[2,3′]Bipyridinyl-6′-yl-1-(2,3-dihydro-benzofuran-5-yl)-2,3,4,9-tetrahydro-1H-β-carboline(#191)

A:2-(5-Bromo-pyridin-2-yl)-1-(2,3-dihydro-benzofuran-5-yl)-2,3,4,9-tetrahydro-1H-β-carboline

1-(2,3-dihydro-5-benzofuranyl)-2,3,4,9-tetrahydro-1H-β-carboline (11.6g, 40 mmol), 2,5-dibromopyridine (10.42 g, 44 mmol), Pd₂dba₃ (1.465 g,1.6 mmol), dppp (1.32 g, 3.2 mmol) and NaOtBu (5.38 g, 56 mmol) werestirred in 60 mL DMF at 80° C. for 3 days. The reaction mixture wasfiltered through a plug of Celite with CH₂Cl₂. The reaction mixture wasthen concentrated, the crude mixture was then loaded on Foxy column (110g silica gel) and eluted with ethyl acetate/hexane (3:7). The productcrystallized out in test tubes. The product was concentrated and thenrecrystallized from THF to yield the product as yellow crystals.

¹H NMR 400 MHz (THF-d8) δ0.91 (m, 1H), 1.15 (m, 1H), 1.25(t, 2H, J=9.5Hz), 1.60 (m, 1H), 2.31 (m, 1H), 2.60 (t, 2H, J=9.5 Hz), 4.75 (d, 1H,J=7.6 H), 5.02 (d, 1H, J=7.6 Hz), 5.10˜5.28 (m, 4H), 5.380 (m, 2H), 5.58(m, 1H), 5.72 (m, 1H), 6.28 (s, 1H), 8.12 (s, 1H)

MS (m/z) 446, 448 (MH⁺), 444, 446 (MH⁻).

B:2-[2,3′]Bipyridinyl-6′-yl-1-(2,3-dihydro-benzofuran-5-yl)-2,3,4,9-tetrahydro-1H-β-carboline

The product from step A above, (0.4 g, 0.896 mmol),2-tributylstannanyl-pyridine (0.8 g, 2.17 mmol) and Pd(PPh₃)₄ (0.12 g,0.104 mmol) were stirred in 1,4-dioxane (5 mL) at 88° C. for 24 h. Thereaction mixture was filtered through a plug of Celite with CH₂Cl₂ andthen concentrated to a small volume. Preparative TLC (3:7 ethylacetate/hexane; then 5% CH₃OH/CH₂Cl₂) yielded the product as a yellowsolid.

¹H NMR (CDCl₃) δ2.82 (m, 1H), 3.10 (m, 3H), 3.58 (m, 1H), 4.31 (m, 1H),4.53 (t, 2H, J=9.5 z), 6.71 (, d, 1H, J=7.6 Hz), 6.85 (d, 1H, J=7.6 Hz)

MS (m/z) 445, (MH⁺), 443 (MH⁻)

Following procedures as described herein, the compounds as listed inTables 1-6 were prepared.

TABLE 1

Cmpd # R^(D) R²

R³ 1 H 3,4-methylenedioxyphenyl — — 2 dimethylaminoethyl3,4-methylenedioxyphenyl 2-benzothiazolyl — 3 H 3,4-methylenedioxyphenyl2-benzothiazolyl — 4 dimethylaminoethyl 3,4-methylenedioxyphenyl2-pyrimidinyl 5-(4-chlorophenyl) 5 dimethylaminoethyl3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(3,4-di-methoxyphenyl) 6dimethylaminoethyl 3,4-methylenedioxyphenyl 2-pyrimidinyl5-(4-methoxyphenyl) 7 H 3,4-methylenedioxyphenyl 2-pyrimidinyl5-(3,4-dimethoxyphenyl) 8 H 3,4-methylenedioxyphenyl 2-pyrimidinyl5-(2-nitro-4-methylsulfonyl)phenyl 9 H 3,4-methylenedioxyphenyl2-pyrimidinyl 5-(4-methoxyphenyl) 10 H 3,4-methylenedioxyphenyl2-pyrimidinyl 5-(4-chlorophenyl 148 2-(N-pyrrolidinyl)ethyl3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(4-methoxyphenyl) 1502-benzoxazolyl 3,4-methylenedioxyphenyl 2-benzoxazolyl — 151 H3,4-methylenedioxyphenyl 2-benzoxazolyl — 153 H 3,4-methylenedioxyphenyl2-pyrimidinyl 5-(2-pyridyl) 154 2-(N-pyrrolidinyl)ethyl3,4-methylenedioxyphenyl 2-pyrimidinyl5-(2-nitro-4-methylsulfonylphenyl) 155 dimethylaminoethyl3,4-methylenedioxyphenyl 2-benzoxazolyl — 156 dimethylaminoethyl3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(2-pyridyl) 161 H3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(4-methylphenyl) 1665-(4-methylphenyl)-2-pyrimidinyl 3,4-methylenedioxyphenyl 2-pyrimidinyl5-(4-methylphenyl) 167 H 3,4-dimethoxyphenyl 2-pyrimidinyl5-(3,4-dimethoxyphenyl) 168 H 3,4-methylenedioxyphenyl 2-pyrimidinyl —169 H 3,4-methylenedioxyphenyl 2-thiazolyl 4-(4-methoxyphenyl) 170 H3,4-methylenedioxyphenyl 2-thiazolyl 4-phenyl 172 H3,4-methylenedioxyphenyl 2-benzimidazolyl — 173 H3,4-methylenedioxyphenyl 2-pyrimidinyl — 174 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-(4-methoxyphenyl 175 H3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(3,4-dimethoxyphenyl) 176 HR-3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(3,4-dimethoxyphenyl) 177 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-(4-hydroxyphenyl) 178 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl5-(4-[2-(N-pyrrolidinyl)ethoxy]phenyl) 179 H 3,4-methylenedioxyphenyl2-pyrimidinyl 5-bromo 180 H 5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl5-(4-(2-(4-morpholinyl)ethoxy)phenyl) 181 H 5-(2,3-dihydro)-benzofuryl2-pyrimidinyl 5-(4-(2-(dimethylamino)ethoxy)phenyl 182 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-(2-pyridyl) 183 H3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(2-pyridyl) 184 H6-(2,3-dihydrobenzo-[1,4]-dioxin-6-yl) 2-pyrimidinyl 5-(4-methoxyphenyl)185 H 5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-(3-pyridyl) 186 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-bromo 187 H5-(2,3-dihydro)-benzofuryl 2-pyrimidinyl 5-(2-pyridyl) 188 H6-(2,3-dihydrobenzo-[1,4]-dioxin-6-yl) 2-pyrimidinyl 5-(4-methoxyphenyl)189 H 3,4-methylenedioxyphenyl 2-pyrimidinyl 5-(2-pyridyl) 190 H5-(2,3-dihydrobenzofuryl) 2-pyrimidinyl5-(2,3-dimethyl-3H-imidazol-4-yl) 191 H 5-(2,3-dihydrobenzofuryl2-pyridyl 5-(2-pyridyl)

TABLE 2

Cmpd # R^(D) R² Y

R³ 11 H 3,4-methylenedioxyphenyl CH₂ 2-furyl5-(2-chloro-5-trifluoromethylphenyl) 12 H 3,4-methylenedioxyphenyl CH₂2-furyl 5-(3-trifluoromethylphenyl) 13 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-benzo(b)furyl 5-nitro 14 H3,4-methylenedioxyphenyl C(O) 2-benzo(b)furyl 5-nitro 15 H3,4-methylenedioxyphenyl C(O) 2-benzo(b)furyl 6-methoxy 16 H3,4-methylenedioxyphenyl C(O) 2-benzo(b)furyl — 17 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-ben- — zo(b)thienyl 18 H3,4-methylenedioxyphenyl C(O) 2-ben- — zo(b)thienyl 19 2-(3-nitro-3,4-(difluoromethylenedioxy)phenyl C(O) 2-furyl 5-(3-nitrophenyl)phenyl)-5-furylcarbonyl 20 2-(3-trifluoro-3,4-(difluoromethylenedioxy)phenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) methylphenyl)-5-furyl- carbonyl 21 H3,4-(difluoromethylenedioxy)phenyl C(O) 2-furyl 5-(3-nitrophenyl) 22 H3,4-(difluoromethylenedioxy)phenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 23 2-methoxycarbonylethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 242-methoxycarbonylmethyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(3-nitrophenyl) 25 2-methoxycarbonylmethyl 3,4-methylenedioxyphenylC(O) 2-furyl 5-(3-trifluoromethylphenyl) 26 2-pyridylmethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 274-chloro-n-butyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 28 4-morpholinylethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 29carboxyethyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 30 carboxymethyl 3,4-methylenedioxyphenylC(O) 2-furyl 5-(3-nitrophenyl) 31 carboxymethyl 3,4-methylenedioxyphenylC(O) 2-furyl 5-(3-trifluoromethylphenyl) 33 diethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 34dimethylaminobutyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 35 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 36dimethylaminoethyl 3,4-methylenedioxyphenyl C(O) 2-furyl 5-t-butyl 37dimethylaminoethyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(4-nitrophenyl) 38 dimethylaminoethyl 3,4-methylenedioxyphenyl C(O)2-furyl 5-(3-nitrophenyl) 39 dimethylaminoethyl 3,4-methylenedioxyphenylC(O) 2-furyl 5-(4-chlorophenyl) 40 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitro-4-chlorophenyl) 41dimethylaminoethyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(2-nitrophenyl) 42 dimethylaminoethyl 3,4-methylenedioxyphneyl C(O)2-furyl 5-(2-nitro-4-methylphenyl) 43 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-furyl5-(2-chloro-5-trifluoromethylphenyl) 44 dimethylaminopropyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 744-pyridylmethyl 3,4-methylenedioxyphenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 75 pyrrolidinylethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 45 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(4-aminophenyl) 46 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(4-chlorophenyl) 47 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitro-4-chlorophenyl) 48 H3,4-methylenedioxyphenyl C(O) 2-furyl5-[4-(3-carboxy)-n-propylcarbonylaminophenyl] 49 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(4-acetylaminophenyl 50 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(4-nitrophenyl) 51 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitro-4-chloro phenyl) 52 H3,4-methylenedioxyphenyl C(O) 2-furyl5-[4-(3-carboxy)-n-propylcarbonylaminophenyl] 53 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitro-4-methylphenyl) 54 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-nitrophenyl) 55 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(3-acetylaminophenyl) 56 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitrophenyl) 57 H3,4-methylenedioxyphenyl C(O) 2-furyl5-(2-chloro-5-trifluoromethylphenyl) 58 H 3,4-methylenedioxyphenyl C(O)2-furyl 5-(3-trifluoromethylphenyl) 59 H 3,4-methylenedioxyphenyl C(O)2-furyl 5-(3-aminophenyl) 60 H 3,4-methylenedioxyphenyl C(O) 2-furyl5-[4-(4-hydroxy-n-butyl)aminophenyl] 61 H 3,4-methylenedioxyphenyl C(O)2-furyl 5-[2-(dimethylamino)methyl- carbonylaminophenyl] 62 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-trifluoromethyl 63 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-bromo 64 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-nitro 65 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-t-butyl 66 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-(2-nitro-4-chlorophenyl) 78 H3-pyridyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 79 H 4-chlorophenylC(O) 2-furyl 5-(trifluoromethylphenyl) 80 H 4-cyanophenyl C(O) 2-furyl5-(3-nitrophenyl 81 H 4-cyanophenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 82 H 4-dimethylaminophenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 83 H 4-dimethylaminophenyl C(O) 2-furyl5-(3-nitrophenyl) 84 H 4-nitrophenyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 85 H 4-nitrophenyl C(O) 2-furyl5-(3-nitrophenyl) 86 H 4-pyridyl C(O) 2-furyl 5-(3-nitrophenyl) 87 H4-pyridyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 88 H phenyl C(O)2-furyl 5-(3-trifluoromethylphenyl) 89 H 3,4-methylenedioxyphenyl C(O)2-thiazolyl 4-methyl-5-(4-trifluoromethylphenyl) 90 H3,4-methylenedioxyphenyl C(O) 2-thienyl 4-phenyl-5-trifluoromethyl 91 H3,4-methylenedioxyphenyl C(O) 2-thienyl 5-(4-chlorophenyl) 92 H3,4-dimethylphenyl C(O) 3-(1,2,5-tri- 1-phenyl-4-methyl azolyl) 93 H3,4-dichlorophenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl) 94 H3,4-dimethoxyphenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl) 95 H3,4-dimethylphenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl) 96 H3,4-methylenedioxyphenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl) 97H 3,4-methylenedioxyphenyl C(O) 3-(1,2,5-tria- 5-(3-pyridyl) zolyl) 98 H3-trifluoromethyl-4-chlorophenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methylzolyl) 99 H 4-cyanophenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl)100 H 4-methoxycarbonylphenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methylzolyl) 101 H 4-methoxyphenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methylzolyl) 102 H 4-nitrophenyl C(O) 3-(1,2,5-tria- 1-phenyl-4-methyl zolyl)103 dimethylaminoethyl 3,4-methylenedioxyphenyl C(O) 3-furyl2-methyl-5-(4-chloro phenyl) 104 H 3,4-methylenedioxyphenyl C(O) 3-furyl2-methyl-5-phenyl 105 H 3,4-methylenedioxyphenyl C(O) 3-furyl2-trifluoromethyl-5-(4-chlorophenyl) 106 H 3,4-methylenedioxyphenyl C(O)3-pyrazolyl 1-phenyl-5-methyl 107 H 4-[N-(3-dimethyl- C(O) 3-pyrazolyl1-phenyl-5-methyl amino)-n-propoxy]phenyl 108 H 3,4-methylenedioxyphenylC(O) 3-pyridyl 6-chloro 109 H 3,4-dichlorophenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 110 H 3,4-dimethoxyphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 111 H 3,4-dimethylphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 112 H 3,4-methylenedioxyphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 113 H 3,5-dimethylphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 114 H 3-trifluoromethyl-4-chlorophenyl C(O)4-isoxazolyl 3-phenyl-5-methyl 115 H 4-cyanophenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 116 H 4-methoxycarbonylphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 117 H 4-methoxyphenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 118 H 4-nitrophenyl C(O) 4-isoxazolyl3-phenyl-5-methyl 119 H 3,4-dimethylphenyl C(O) 4-pyrazolyl1-phenyl-5-trifluoromethyl 120 H 3,4-dichlorophenyl C(O) 4-pyrazolyl1-phenyl-5-trifluoromethyl 121 H 3,4-dimethoxyphenyl C(O) 4-pyrazolyl1-phenyl-5-trifluoromethyl 122 H 3,4-methylenedioxyphenyl C(O)4-pyrazolyl 1-phenyl-5-n-propyl 123 H 3,4-methylenedioxyphenyl C(O)4-pyrazolyl 1-phenyl-5-trifluoromethyl 124 H 3,4-methylenedioxyphenylC(O) 4-pyrazolyl 1-(4-chlorophenyl)-5-trifluoromethyl 125 H3,4-methylenedioxyphenyl C(O) 4-pyrazolyl1-(4-nitrophenyl)-5-trifluoromethyl 126 H 3,5-dimethylphenyl C(O)4-pyrazolyl 1-phenyl-5-trifluoromethyl 127 H3-trifluoromethyl-4-chlorophenyl C(O) 4-pyrazolyl1-phenyl-5-trifluoromethyl 128 H 4-cyanophenyl C(O) 4-pyrazolyl1-phenyl-5-trifluoromethyl 129 H 4-methoxycarbonylphenyl C(O)4-pyrazolyl 1-phenyl-5-trifluoromethyl 130 H 4-methoxyphenyl C(O)4-pyrazolyl 1-phenyl-5-trifluoromethyl 131 H 4-nitrophenyl C(O)4-pyrazolyl 1-phenyl-5-trifluoromethyl 132 H 3,4-methylenedioxyphenylC(O) 4-thiazolyl 2-(4-pyrazinyl) 133 H 3,4-dichlorophenyl C(O)5-pyrazolyl 1-benzyl-3-t-butyl 134 H 3,4-dimethoxyphenyl C(O)5-pyrazolyl 1-benzyl-3-t-butyl 135 H 3,4-dimethylphenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 136 H 3,4-methylenedioxyphenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 137 H 3,5-dimethylphenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 138 H 3-trifluoromethyl-4-chlorophenyl C(O)5-pyrazolyl 1-benzyl-3-t-butyl 139 H 4-cyanophenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 140 H 4-methoxycarbonylphenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 141 H 4-methoxyphenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 142 H 4-nitrophenyl C(O) 5-pyrazolyl1-benzyl-3-t-butyl 143 dimethylaminoethyl 3,4-methylenedioxyphenyl C(O)naphthyl — 144 H 3,4-methylenedioxyphenyl C(O) naphthyl — 145 H3,4-methylenedioxyphenyl SO₂ 2-thienyl 5-phenylsulfonyl 146 H3,4-methylenedioxyphenyl SO₂ 2-thienyl 3-phenylsulfonyl 147dimethylaminoethyl 3,4-methylenedioxyphenyl C(O) 2-benzofuryl — 149 H3,4-methylenedioxyphenyl C(O) 2-furyl 5-phenyl 152 dimethylaminoethyl3,4-methylenedioxyphenyl C(O) 2-furyl 5-phenyl 185 H3,4-methylenedioxphenyl CH₂ phenyl —

TABLE 3

Cmpd # R² R⁴ Y

R³ 67 3,4-methylenedioxyphenyl carboxy C(O) 2-furyl 5-(3-nitrophenyl) 683,4-methylenedioxyphenyl 2-(dimethylamino)ethoxycarbonyl C(O) 2-furyl5-(3-nitrophenyl) 69 3,4-methylenedioxyphenyl2-(dimethylamino)ethylaminocarbonyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 70 3,4-methylenedioxyphenyl carboxy C(O)2-furyl 5-(3-trifluoromethylphenyl) 71 3,4-methylenedioxyphenylmethoxycarbonyl C(O) 2-furyl 5-(3-trifluoromethylphenyl) 723,4-methylenedioxyphenyl methoxycarbonyl C(O) 2-furyl5-(3-trifluoromethylphenyl) 73 3,4-methylenedioxyphenyl methoxycarbonylC(O) 2-furyl 5-(3-nitrophenyl)

TABLE 4

Cmpd # R² Y

R³ 76 3,4-methylene- C(O) 2-furyl 5-(3-nitrophenyl) dioxyphenyl 773,4-methylene- C(O) 2-furyl 5-(4-chlorophenyl) dioxyphenyl

TABLE 5

Cmpd # R² Z

R³ 157 3,4-methylene- C(O) 2-pyrimi- 5-(3,4-dimethoxyphenyl) dioxyphenyldinyl 158 3,4-methylene- CHOH 2-pyrimi- 5-(3,4-dimethoxyphenyl)dioxyphenyl dinyl 159 3,4-methylene- C(O) 2-pyrimi- 5-(4-methylphenyl)dioxyphenyl dinyl 160 3,4-methylene- CHOH 2-pyrimi- 5-(4-methylphenyl)dioxyphenyl dinyl 162 3,4-methylene- C(O) 2-pyrimi- 5-(4-methoxyphenyl)dioxyphenyl dinyl 163 3,4-methylene- C(O) 2-pyrimi- 5-(4-methoxyphenyl)dioxyphenyl dinyl 164 3,4-methylene- CHOH 2-pyrimi- 5-(4-methoxyphenyl)dioxyphenyl dinyl 165 3,4-methylene- C(O) 2-pyrimi- 5-(4-methoxyphenyl)dioxyphenyl dinyl

EXAMPLE 10 In Vitro Testing

Cyclic Nucleotide Phosphodiesterase (PDE) Assay PDEV Isolation

PDEV was isolated from rabbit and human tissues according to theprotocol described by Boolell et al. (Boolell, M., Allen, M. J.,Ballard, S. A., Ge[o-Attee, S., Muirhead, G. J., Naylor, A. M.,Osterloh, I. H., and Gingell, C) in International Journal of ImpotenceResearch 1996 8, 47-52 with minor modifications.

Briefly, rabbit or human tissues were homogenized in an ice-cold buffersolution containing 20 mM HEPES (pH 7.2), 0.25M sucrose, 1 mM EDTA, and1 mM phenylmethylsulphonyl fluoride (PMSF). The homogenates werecentrifuged at 100,000 g for 60 minutes at 4° C. The supernatant wasfiltered through 0.2 μM filter and loaded on a Pharmacia Mono Q anionexchange column (1 ml bed volume) that was equilibrated with 20 mMHEPES, 1 mM EDTA and 0.5 mM PMSF. After washing out unbound proteins,the enzymes were eluted with a linear gradient of 100-600 mM NaCl in thesame buffer (35 to 50 ml total, depending on the tissue. Enzymes fromthe skeletal muscle, corpus cavernosum, retina, heart and platelet wereeluted with 35, 40, 45, 50, and 50 ml respectively.) The column was runat a flow rate of 1 ml/min and 1 ml fractions were collected. Thefractions comprising various PDE activities were pooled separately andused in later studies.

Measurement of Inhibition of PDEV

The PDE assay was carried out as described by Thompson and Appleman inBiochemistry 1971 10, 311-316 with minor modifications, as noted below.

The assays were adapted to a 96-well format. The enzyme was assayed in 5mM MgCl₂, 15 mM Tris HCl (pH 7.4), 0.5 mg/ml bovine serum albumin, 1 μMcGMP or cAMP, 0.1 μCi [³H]-cGMP or [³H]-cAMP, and 2-10 μl of columnelution. The total volume of the assay was 100 μl. The reaction mixturewas incubated at 30° C. for 30 minutes. The reaction was stopped byboiling for 1 minute and then cooled down on ice. The resulting [³H]5′-mononucleotides were further converted to uncharged [³H]-nucleosidesby adding 25 μl 1 mg/ml snake venom (Ophiophagus hannah) and incubatingat 30° C. for 10 minute. The reaction was stopped by the addition of 1ml Bio-Rad AG1-X2 resin slurry (1:3). All the charged nucleotides werebound by the resin and only the uncharged [³H]-nucleosides remained inthe supernatant after centrifuging. An aliquot of 200 μl was taken andcounted by liquid scintillation. PDE activity was expressed as pmolcyclic nucleotide hydrolyzed/min/ml of enzyme preparation.

Inhibitor studies were carried out in assay buffer with a finalconcentration of 10% DMSO. Under these conditions, the hydrolysis ofproduct increased with time and enzyme concentration in a linearfashion.

EXAMPLE 11 In Vitro Determination of K_(i) for PhosphodiesteraseInhibitors

The assay was adapted to a 96-well format. Phosphodiesterase was assayedin 5 mM MgCl₂, 15 mM Tris HCl (pH 7.4), 0.5 mg/ml bovine serum albumin,30 nM ³H-cGMP and test compound at various concentrations. The amount ofenzyme used for each reaction was such that less than 15% of the initialsubstrate was converted during the assay period. For all measurements,the test compound was dissolved and diluted in 100% DMSO (2% DMSO inassay). The total volume of the assay was 100 μl. The reaction mixturewas incubated at 30° C. for 90 minutes. The reaction was stopped byboiling for 1 minute and then immediately cooled by transfer to an icebath. To each well was then added 25 μl 1 mg/ml snake venom (Ophiophagushannah) and the reaction mixture incubating at 30° C. for 10 minute. Thereaction was stopped by the addition of 1 ml Bio-Rad AG1-X2 resin slurry(1:3). An aliquot of 200 μl was taken and counted by liquidscintillation.

The % inhibition of the maximum substrate conversion (by the enzyme inthe absence of inhibitor) was calculated for each test compoundconcentration. Using GraphPad Prism′s nonlinear regression analysis(sigmoidal dose response), the % inhibition vs log of the test compoundconcentration was plotted to determine the IC₅₀. Under conditions wheresubstrate concentration <<K_(m) of the enzyme (K_(m)=substrateconcentration at which half of the maximal velocity of the enzyme isachieved), K_(i) is equivalent to the IC₅₀ value.

Mass spec and PDEV inhibitory activity for representative compounds ofthe present invention are described in Tables 6-7. Inhibitory data ispresented either as the IC₅₀ (μM), as a percent inhibition at a givenconcentration of test compound or as a Ki value.

TABLE 6 % Inh @ 10 μM Cmpd # MW MS (M + 1) (rabbit) 1 288.30 289 67 2496.63 497 43 3 425.51 426 84 4 552.08 553 94 5 577.68 578 6 547.66 54895 7 506.56 507 91 8 569.60 580 89 9 476.53 477 80 10 480.95 481 79 11550.96 551 53 12 516.52 517 76 13 552.58 553 94 14 481.46 482 88 15466.49 467 90 16 436.47 437 88 17 523.65 524 88 18 452.53 453 87 19758.64 759 15 20 804.64 805 4 21 543.48 544 32 22 566.48 567 16 23616.59 617 30 24 579.56 580 40 25 602.56 603 20 26 621.61 622 88 27621.05 622 56 28 643.66 644 94 29 602.56 601* (M − 1) 79 No M + 1 ion 30565.54 564 93 31 588.54 587* (M − 1) 75 no M + 1 ion 33 629.68 630 88 33629.68 630 63 34 629.68 630 67 35 601.62 602 98 36 513.63 514 97 37578.62 579 95 38 578.62 579 91 39 568.07 569 93 40 613.07 614 78 41578.62 579 93 42 592.65 593 89 43 636.07 637 22 44 615.65 616 65 45477.52 478 46 496.95 497 47 541.94 542 83 48 577.59 578 60 49 519.55 52060 50 507.50 508 76 51 541.94 542 52 577.59 578 76 53 521.53 522 85 54507.50 508 81 55 519.55 520 70 56 507.50 508 57 564.95 565 76 58 530.50531 59 477.52 478 92 60 549.62 550 89 61 562.62 563 90 62 454.40 455 8663 465.30 465 78 64 431.40 432 83 65 442.51 443 66 66 541.94 542 23 67550.50 549* (M − 1) 50 No M + 1 ion 68 622.63 623 35 69 644.65 645 21 70574.51 573 46 71 588.54 587* (M − 1) 21 No M + 1 ion 72 588.54 587* (M− 1) 15 No M + 1 ion 73 565.54 564* (M − 1) 20 No M + 1 ion 74 621.61622 84 75 627.66 628 76 524.55 525 27 77 514.00 515 58 78 487.48 488 3579 520.94 521 37 80 488.50 489 27 81 511.50 510* (M − 1) 18 No M + 1 ion82 529.56 530 13 83 506.56 507 27 84 531.49 532 20 85 508.49 509 26 86464.48 465 69 87 487.48 488 34 88 486.49 487 49 89 561.58 562 90 546.57547 69 91 513.01 514 82 92 461.57 462 39 93 502.40 503 44 94 493.56 49419 95 461.57 462 13 96 477.52 478 57 97 480.55 481 71 98 535.95 536 3899 458.52 459 40 100 491.55 492 24 101 463.54 464 48 102 478.51 479 40103 510.97 511 55 104 476.53 477 72 105 564.95 565 40 106 476.53 477 70107 533.67 534 15 108 431.88 432 48 109 502.40 503 31 110 493.56 494 32111 461.56 462 35 112 477.52 478 33 113 461.56 462 29 114 535.95 536 27115 458.52 459 30 116 491.54 492 32 117 463.53 464 32 118 478.51 479 28119 514.55 515 28 120 555.39 556 18 121 546.55 547 10 122 504.59 505 65123 530.50 531 56 124 564.95 565 53 125 575.50 576 54 126 514.55 515 12127 588.94 589 13 128 511.51 512 11 129 544.53 545 46 130 516.52 517 45131 531.49 532 12 132 480.55 481 76 133 557.52 556 1 134 548.68 547 5135 516.69 517 8 136 532.64 533 18 137 516.69 517 −3 138 591.07 592 13139 513.64 514 −9 140 546.67 547 8 141 518.66 519 11 142 533.63 534 −5143 517.63 518 60 144 446.50 447 76 145 578.69 579* (M − 1) 43 No M + 1ion 146 578.69 579 35

TABLE 7 % INH @ 10 μM Cmpd # MW MS (M + 1) IC₅₀ (μM) (rabbit) 147 507.59508 5.2  52 148 573.69 574 4.4  66 149 462.50 463 0.75  80 150 526.55527  4 151 409.44 410 0.13  95 152 533.63 534 1.2  80 153 447.50 4480.12  95 154 666.76 667 0.11  97 155 480.56 481 9.2  57 156 518.62 5190.0075 157 520.54 521 0.0087^(a) 158 522.56 523  49 159 474.52 475 0.024160 476.53 477 8.95 161 460.54 461 0.789 162 490.52 491 0.024^(a) 164492.53 493  82 166 628.73 629  58 167 522.60 523 1.49 168 370.41 3712.15^(a) 169 481.57 482 0.042 170 451.55 452 0.049 172 408.46 409 44^(a) 174 474.56 475 0.150^(a) 175 506.56 507 0.214 176 506.56 5070.056 178 557.70 558  37 179 449.31 450 1.58 180 573.69 574  40 182445.52 446 0.058 183 447.50 448 0.122^(a) 184 0.640^(a) 185 446200.40^(a) 186 448 240.10^(a) 187 446  49.79^(a) 188 491 642.69^(a) 189448 121.60^(a) 190 463 Ki = 14.21 nM 191 443 Ki = 0.69 nM  ^(a)Compoundstested using human tissue.

EXAMPLE 12 In Vivo Testing

Following the procedure disclosed by Carter et al., (Carter, A. J.,Ballard, S. A., and Naylor, A. M.) in The Journal of Urology 1998, 160,242-246, compounds of the present invention are tested for in vivoefficacy.

EXAMPLE 13

As a specific embodiment of an oral composition, 100 mg of the compoundof Example 7 is formulated with sufficient finely divided lactose toprovide a total amount of 580 to 590 mg to fill a size O hard gelcapsule.

While the foregoing specification teaches the principles of the presentinvention, with examples provided for the purpose of illustration, itwill be understood that the practice of the invention encompasses all ofthe usual variations, adaptations and/or modifications as come withinthe scope of the following claims and their equivalents.

1. A compound of the formula (I):

wherein R¹ is independently selected from the group consisting ofhalogen, nitro, hydroxy, C₁-C₈alkyl, C₁-C₈alkoxy, —NH₂, —NHR^(A),—N(R^(A))₂, —O—R^(A), —C(O)NH₂, —C(O)NHR^(A), —C(O)N(R^(A))₂,—NC(O)—R^(A), —SO₂NHR^(A), —SO₂N(R^(A))₂, phenyl (optionally substitutedwith 1 to 3 R^(B)) and heteroaryl (optionally substituted with 1 to 3R^(B)); where each R^(A) is independently is independently selected fromthe group consisting of C₁-C₈alkyl, aryl (optionally substituted with 1to 3 R^(B)), C₁-C₈aralkyl (optionally substituted with 1 to 3 R^(B)) andheteroaryl (optionally substituted with 1 to 3 R^(B)); where each R^(B)is independently selected from the group consisting of halogen, hydroxy,nitro, cyano, C₁-C₈alkyl, C₁-C₈alkoxy, C₁-C₈alkoxycarbonyl,carboxyC₁-C₈alkyl, C₁-C₈alkylsulfonyl, trifluoromethyl,trifluoromethoxy, amino, acetylamino, di(C₁-C₈alkyl)amino,di(C₁-C₈alkyl)aminoC₁-C₈alkoxy, di(C₁-C₈alkyl)aminoacetylC₁-C₈alkyl,di(C₁-C₈alkyl)aminoacetylamino, carboxyC₁-C₈alkylcarbonylamino,hydroxyC₁-C₈alkylamino, NHR^(A,) N(R^(A))₂ andheterocycloalkylC₁-C₈alkoxy; n is an integer from 0 to 4; X is selectedfrom the group consisting of O and S; R² is selected from the groupconsisting of C₅-C₁₀alkyl (optionally substituted with 1 to 3 R^(C)),aryl (optionally substituted with 1 to 3 R^(B)), heteroaryl (optionallysubstituted with 1 to 3 R^(B)) and heterocycloalkyl (optionallysubstituted with 1 to 3 R^(B)); where each R^(C) is independentlyselected from the group consisting of halogen, hydroxy, nitro, NH₂,NHR^(A) and N(R^(A))₂; Z is CH₂; R⁴ is selected from the groupconsisting of hydrogen, hydroxy, carboxy, C₁-C₆alkylcarbonyl,C₁-C₆alkoxylcarbonyl, di-(C₁-C₈alkyl)aminoalkoxycarbonyl,di(C₁-C₈alkyl)aminoC₁-C₈alkylaminocarbonyl, and —COR^(F); where R^(F) isselected from the group consisting of C₁C₈alkyl, NH₂, NHR^(A), NR^(A) ₂,—C₁-C₈alkyl-NH₂, —C₁-C₈alkyl-NHR^(A), —C₁-C₈alkyl-NR^(A) ₂ and—NH—C₁-C₈alkyl-NR^(A) ₂; a is an integer from 0 to 1; Y is selected fromthe group consisting of CH₂, C(O), C(O)O, C(O)—NH and SO₂;

 is selected from the group consisting of naphthyl, heteroaryl andheterocycloalkyl; m is an integer from 0 to 2; R³ is independentlyselected from the group consisting of halogen, nitro, C₁-C₈alkyl,C₁-C₈alkoxy, trifluoromethyl, trifluoromethoxy, phenyl (optionallysubstituted with 1 to 3 R^(B)), phenylsulfonyl, naphthyl, C₁-C₈aralkyl,heteroaryl (optionally substituted with 1 to 3 R^(B)), NH₂, NHR^(A) andN(R^(A))₂; provided that when

 is 2-furyl or 2-thienyl, then in is an integer from 1 to 2; andpharmaceutically acceptable salts thereof.
 2. The compound of claim 1wherein n is 0; X is S; where each R^(B) is independently selected fromthe group consisting of halogen, nitro, C₁-C₄alkyl, C₁-C₄alkoxy,trifluoromethyl, trifluoromethoxy, amino and di(C₁-C₄ alkyl)amino; R² isselected from the group consisting of 3,4-methylenedioxyphenyl,3,4-(difluoro)methylenedioxyphenyl, 2,3-dihydrobenzofuryl,2,3-dihydrobenzo-[1,4]-dioxin-6-yl, pyridyl, phenyl and substitutedphenyl; wherein the phenyl substituents are one to two substituentsindependently selected from halogen, C₁-C₄alkyl, C₁-C₄alkoxy,trifluoromethyl, cyano, nitro, C₁-C₄alkoxycarbonyl, di(C₁-C₄alkyl)aminoor di(C₁-C₄alkyl)aminoC₁-C₄alkoxy; R⁴ selected from the group consistingof hydrogen, carboxy, C₁-C₄alkoxycarbonyl,di(C₁-C₄alkyl)aminoC₁-C₄alkoxycarbonyl anddi(C₁-C₄alkyl)aminoC₁-C₄alkylaminocarbonyl; Y is selected from the groupconsisting of C(O), SO₂ and CH₂;

 is selected from the group consisting of naphthyl and heteroaryl; R³independently selected from the group consisting of halogen, nitro,C₁-C₄alkyl, C₁-C₄alkoxy, trifluoromethyl, C₁-C₄aralkyl, pyrazinyl,pyridyl, halogen substituted pyridyl, dimethyl substituted imidazolyl,phenyl, phenylsulfonyl and substituted phenyl; wherein the substituentson the phenyl are one or more substituents independently selected fromhalogen, hydroxy, C₁-C₄alkyl, C₁-C₄alkoxy, trifluoromethyl,trifluoromethoxy, nitro, amino, acetylamino, C₁-C₄alkylsulfonyl,carboxyC₁-C₄alkylcarbonylamino, hydroxyC₁-C₄alkylamino,di(C₁-C₄alkyl)aminoC₁-C₄alkoxy, di(C₁-C₄alkyl)aminoacetylamino orheterocycloalkylC₁-C₄alkoxy; provided that when

 is 2-furyl or 2-thienyl, then m is an integer from 1 to 2; andpharmaceutically acceptable salts thereof.
 3. The compound of claim 2,wherein X is S; R² is selected from the group consisting of phenyl,3,4-methylenedioxyphenyl, 3,4-(difluoro)methylenendioxyphenyl,2,3-dihydrobenzofuryl, 2,3-dihydrobenzo-[1,4]-dioxin-6-yl, 4-pyridyl,3-pyridyl, 4-cyanophenyl, 3-nitrophenyl, 4-nitrophenyl,4-trifluoromethylphenyl, 4-methoxyphenyl, 3,4-dimethylphenyl,3,5-dimethylphenyl, 3,4-dimethoxyphenyl,3-trifluoromethyl-4-chlorophenyl, 3,4-dichlorophenyl, 4-chlorophenyl,4-methoxycarbonylphenyl, 3,4-dimethoxyphenyl, 4-(dimethylamino)phenyland 4-(N-(3-dimethylamino)-n-propoxy)phenyl; R⁴ is selected from thegroup consisting of hydrogen, carboxy, dimethylaminoethoxycarbonyl,dimethylaminoethylaminocarbonyl and methoxycarbonyl;

 is selected from the group consisting of naphthyl, 2-pyrimidinyl,2-furyl, 3-furyl, 2-benzofuryl, 2-theinyl, 2-benzothienyl,2-benzothiazolyl, 2-benzoxazolyl, 2-benzimidazolyl, 4-thiazolyl,2-thiazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 3-(1,2,5-triazolyl),4-isoxazolyl, 2-pyridyl and 3-pyridyl; R³ independently selected fromthe group consisting of chloro, bromo, methyl, n-propyl, t-butyl,methoxy, trifluoromethyl, nitro, phenyl, benzyl, phenylsulfonyl,4-hydroxyphenyl, 4-chlorophenyl, 4-methylphenyl, 3,4-dimethoxyphenyl,3-trifluoromethylphenyl, 4-trifluoromethylphenyl,5-trifluoromethylphenyl, 4-methoxyphenyl, 2-nitrophenyl, 3-nitrophenyl,4-nitrophenyl, 3-aminophenyl, 4-aminophenyl, 2-nitro-4-chlorophenyl,2-nitro-4-methylphenyl, 2-nitro-4-methylsulfonylphenyl,3-acetylaminophenyl, 4-acetylaminophenyl,4-(3-carboxy-n-propyl)carbonylaminophenyl,2-chloro-5-trifluoromethylphenyl, 4-(4-hydroxy-n-butyl)aminophenyl,2-(dimethylamino)acetylaminophenyl, 4-[2-(N-pyrrolidinyl)ethoxy]phenyl,4-[2-(4-morpholinyl)ethoxy]phenyl, 4-(2-(dimethylamino)ethoxy)phenyl,4-pyrazinyl, 2,3-dimethyl-3H-imidazolyl, 2-pyridyl and 3-pyridyl;provided that when

 is 2-furyl or 2-thienyl, then m is an integer from 1 to 2; andpharmaceutically acceptable salts thereof.
 4. A pharmaceuticalcomposition comprising a pharmaceutically acceptable carrier and acompound of claim
 1. 5. A method of treating sexual dysfunction in asubject in need thereof comprising administering to the subject atherapeutically effective amount of the compound of claim
 1. 6. Themethod of treating sexual dysfunction of claim 5, wherein the sexualdysfunction is male erectile dysfunction.
 7. The method of claim 5wherein the sexual dysfunction is selected from the group consisting ofmale sexual dysfunction, male erectile dysfunction, impotence, femalesexual dysfunction, female sexual arousal dysfunction and female sexualdysfunction related to blood flow and nitric oxide production in thetissues of the vagina and clitoris.
 8. A method of treating a conditionselected from the group consisting of male erectile dysfunction (ED),impotence, female sexual arousal dysfunction, female sexual dysfunctionrelated to blood flow and nitric oxide production in the tissues of thevagina and clitoris, premature labor, dysmenorhea, cardiovasculardisorders, atherosclerosis, arterial occlusive disorders, thrombosis,coronary rest stenosis, angina pectoris, myocardial infarction, heartfailure, ischemic heart disorders, hypertension, pulmonary hypertension,asthma, intermittent claudication and diabetic complications in asubject in need thereof comprising administering to the subject atherapeutically effective amount of the compound of claim
 1. 9. Aprocess for making a pharmaceutical composition comprising mixing acompound of claim 1 and a pharmaceutically acceptable carrier.